Method and apparatus for requesting retransmission resource in nr v2x

ABSTRACT

A method for performing wireless communication by a first device and an apparatus for supporting same are provided. The method may comprise: receiving, from a base station, information related to a first sidelink (SL) resource and information related to a first physical uplink control channel (PUCCH) resource; transmitting, to a second device, a medium access control (MAC) packet data unit (PDU) by using the first SL resource, wherein the MAC PDU includes a packet related to a logical channel for which hybrid automatic repeat request (HARQ) feedback is disabled, and wherein the MAC PDU includes no packet related to a logical channel for which HARQ feedback is enabled; determining that retransmission of the MAC PDU is required; and transmitting, to the base station, NACK information by using the first PUCCH resource based on no SL grant available for retransmission of the MAC PDU.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

This disclosure relates to a wireless communication system.

Related Art

Sidelink (SL) communication is a communication scheme in which a directlink is established between User Equipments (UEs) and the UEs exchangevoice and data directly with each other without intervention of anevolved Node B (eNB). SL communication is under consideration as asolution to the overhead of an eNB caused by rapidly increasing datatraffic.

Vehicle-to-everything (V2X) refers to a communication technology throughwhich a vehicle exchanges information with another vehicle, apedestrian, an object having an infrastructure (or infra) establishedtherein, and so on. The V2X may be divided into 4 types, such asvehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I),vehicle-to-network (V2N), and vehicle-to-pedestrian (V2P). The V2Xcommunication may be provided via a PC5 interface and/or Uu interface.

Meanwhile, as a wider range of communication devices require largercommunication capacities, the need for mobile broadband communicationthat is more enhanced than the existing Radio Access Technology (RAT) isrising. Accordingly, discussions are made on services and user equipment(UE) that are sensitive to reliability and latency. And, a nextgeneration radio access technology that is based on the enhanced mobilebroadband communication, massive Machine Type Communication (MTC),Ultra-Reliable and Low Latency Communication (URLLC), and so on, may bereferred to as a new radio access technology (RAT) or new radio (NR).Herein, the NR may also support vehicle-to-everything (V2X)communication.

FIG. 1 is a drawing for describing V2X communication based on NR,compared to V2X communication based on RAT used before NR. Theembodiment of FIG. 1 may be combined with various embodiments of thepresent disclosure.

Regarding V2X communication, a scheme of providing a safety service,based on a V2X message such as Basic Safety Message (BSM), CooperativeAwareness Message (CAM), and Decentralized Environmental NotificationMessage (DENM) is focused in the discussion on the RAT used before theNR. The V2X message may include position information, dynamicinformation, attribute information, or the like. For example, a UE maytransmit a periodic message type CAM and/or an event triggered messagetype DENM to another UE.

For example, the CAM may include dynamic state information of thevehicle such as direction and speed, static data of the vehicle such asa size, and basic vehicle information such as an exterior illuminationstate, route details, or the like. For example, the UE may broadcast theCAM, and latency of the CAM may be less than 100 ms. For example, the UEmay generate the DENM and transmit it to another UE in an unexpectedsituation such as a vehicle breakdown, accident, or the like. Forexample, all vehicles within a transmission range of the UE may receivethe CAM and/or the DENM. In this case, the DENM may have a higherpriority than the CAM.

Thereafter, regarding V2X communication, various V2X scenarios areproposed in NR. For example, the various V2X scenarios may includevehicle platooning, advanced driving, extended sensors, remote driving,or the like.

For example, based on the vehicle platooning, vehicles may move togetherby dynamically forming a group. For example, in order to perform platoonoperations based on the vehicle platooning, the vehicles belonging tothe group may receive periodic data from a leading vehicle. For example,the vehicles belonging to the group may decrease or increase an intervalbetween the vehicles by using the periodic data.

For example, based on the advanced driving, the vehicle may besemi-automated or fully automated. For example, each vehicle may adjusttrajectories or maneuvers, based on data obtained from a local sensor ofa proximity vehicle and/or a proximity logical entity. In addition, forexample, each vehicle may share driving intention with proximityvehicles.

For example, based on the extended sensors, raw data, processed data, orlive video data obtained through the local sensors may be exchangedbetween a vehicle, a logical entity, a UE of pedestrians, and/or a V2Xapplication server. Therefore, for example, the vehicle may recognize amore improved environment than an environment in which a self-sensor isused for detection.

For example, based on the remote driving, for a person who cannot driveor a remote vehicle in a dangerous environment, a remote driver or a V2Xapplication may operate or control the remote vehicle. For example, if aroute is predictable such as public transportation, cloud computingbased driving may be used for the operation or control of the remotevehicle. In addition, for example, an access for a cloud-based back-endservice platform may be considered for the remote driving.

Meanwhile, a scheme of specifying service requirements for various V2Xscenarios such as vehicle platooning, advanced driving, extendedsensors, remote driving, or the like is discussed in NR-based V2Xcommunication.

SUMMARY OF THE DISCLOSURE Technical Objects

Meanwhile, if a base station schedules/allocates SL resource(s) to a TXUE through a SL grant, the TX UE may transmit either a HARQ enable MACPDU or a HARQ disable MAC PDU to an RX UE by using the SL resource(s).In addition, the TX UE may request SL resource(s) for additionalretransmission from the base station. In this case, it is necessary topropose a method for the TX UE to efficiently request SL resource(s) foradditional retransmission from the base station and an apparatussupporting the same.

Technical Solutions

In one embodiment, a method for performing, by a first device, wirelesscommunication is provided. The method may comprise: receiving, from abase station, information related to a first sidelink (SL) resource andinformation related to a first physical uplink control channel (PUCCH)resource; transmitting, to a second device, a medium access control(MAC) packet data unit (PDU) by using the first SL resource, wherein theMAC PDU includes a packet related to a logical channel for which hybridautomatic repeat request (HARQ) feedback is disabled, and wherein theMAC PDU includes no packet related to a logical channel for which HARQfeedback is enabled; determining that retransmission of the MAC PDU isrequired; and transmitting, to the base station, NACK information byusing the first PUCCH resource based on no SL grant available forretransmission of the MAC PDU.

In one embodiment, a first device configured to perform wirelesscommunication is provided. The first device may comprise: one or morememories storing instructions; one or more transceivers; and one or moreprocessors connected to the one or more memories and the one or moretransceivers. For example, the one or more processors may execute theinstructions to: receive, from a base station, information related to afirst sidelink (SL) resource and information related to a first physicaluplink control channel (PUCCH) resource; transmit, to a second device, amedium access control (MAC) packet data unit (PDU) by using the first SLresource, wherein the MAC PDU includes a packet related to a logicalchannel for which hybrid automatic repeat request (HARQ) feedback isdisabled, and wherein the MAC PDU includes no packet related to alogical channel for which HARQ feedback is enabled; determine thatretransmission of the MAC PDU is required; and transmit, to the basestation, NACK information by using the first PUCCH resource based on noSL grant available for retransmission of the MAC PDU.

EFFECTS OF THE DISCLOSURE

The user equipment (UE) may efficiently perform SL communication.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing for describing V2X communication based on NR,compared to V2X communication based on RAT used before NR.

FIG. 2 shows a structure of an NR system, based on an embodiment of thepresent disclosure.

FIG. 3 shows a functional division between an NG-RAN and a SGC, based onan embodiment of the present disclosure.

FIG. 4 shows a radio protocol architecture, based on an embodiment ofthe present disclosure.

FIG. 5 shows a structure of an NR system, based on an embodiment of thepresent disclosure.

FIG. 6 shows a structure of a slot of an NR frame, based on anembodiment of the present disclosure.

FIG. 7 shows an example of a BWP, based on an embodiment of the presentdisclosure.

FIG. 8 shows a radio protocol architecture for a SL communication, basedon an embodiment of the present disclosure.

FIG. 9 shows a UE performing V2X or SL communication, based on anembodiment of the present disclosure.

FIG. 10 shows a procedure of performing V2X or SL communication by a UEbased on a transmission mode, based on an embodiment of the presentdisclosure.

FIG. 11 shows three cast types, based on an embodiment of the presentdisclosure.

FIG. 12 shows a procedure for a TX UE to request retransmissionresource(s) in case a base station allocates SL resource(s) and a PUCCHresource to the TX UE, based on an embodiment of the present disclosure.

FIG. 13 shows a procedure for a TX UE to request retransmissionresource(s) in case a base station allocates SL resource(s) and a PUCCHresource to the TX UE, based on an embodiment of the present disclosure.

FIG. 14 shows a procedure for a TX UE to request retransmissionresource(s) in case a base station allocates SL resource(s) and a PUCCHresource to the TX UE, based on an embodiment of the present disclosure.

FIG. 15 shows a method for a first device to perform wirelesscommunication, based on an embodiment of the present disclosure.

FIG. 16 shows a communication system 1, based on an embodiment of thepresent disclosure.

FIG. 17 shows wireless devices, based on an embodiment of the presentdisclosure.

FIG. 18 shows a signal process circuit for a transmission signal, basedon an embodiment of the present disclosure.

FIG. 19 shows another example of a wireless device, based on anembodiment of the present disclosure.

FIG. 20 shows a hand-held device, based on an embodiment of the presentdisclosure.

FIG. 21 shows a vehicle or an autonomous vehicle, based on an embodimentof the present disclosure.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

In the present disclosure, “A or B” may mean “only A”, “only B” or “bothA and B.” In other words, in the present disclosure, “A or B” may beinterpreted as “A and/or B”. For example, in the present disclosure, “A,B, or C” may mean “only A”, “only B”, “only C”, or “any combination ofA, B, C”.

A slash (/) or comma used in the present disclosure may mean “and/or”.For example, “A/B” may mean “A and/or B”. Accordingly, “A/B” may mean“only A”, “only B”, or “both A and B”. For example, “A, B, C” may mean“A, B, or C”.

In the present disclosure, “at least one of A and B” may mean “only A”,“only B”, or “both A and B”. In addition, in the present disclosure, theexpression “at least one of A or B” or “at least one of A and/or B” maybe interpreted as “at least one of A and B”.

In addition, in the present disclosure, “at least one of A, B, and C”may mean “only A”, “only B”, “only C”, or “any combination of A, B, andC”. In addition, “at least one of A, B, or C” or “at least one of A, B,and/or C” may mean “at least one of A, B, and C”.

In addition, a parenthesis used in the present disclosure may mean “forexample”. Specifically, when indicated as “control information (PDCCH)”,it may mean that “PDCCH” is proposed as an example of the “controlinformation”. In other words, the “control information” of the presentdisclosure is not limited to “PDCCH”, and “PDCCH” may be proposed as anexample of the “control information”. In addition, when indicated as“control information (i.e., PDCCH)”, it may also mean that “PDCCH” isproposed as an example of the “control information”.

A technical feature described individually in one figure in the presentdisclosure may be individually implemented, or may be simultaneouslyimplemented.

The technology described below may be used in various wirelesscommunication systems such as code division multiple access (CDMA),frequency division multiple access (FDMA), time division multiple access(TDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and so on. TheCDMA may be implemented with a radio technology, such as universalterrestrial radio access (UTRA) or CDMA-2000. The TDMA may beimplemented with a radio technology, such as global system for mobilecommunications (GSM)/general packet ratio service (GPRS)/enhanced datarate for GSM evolution (EDGE). The OFDMA may be implemented with a radiotechnology, such as institute of electrical and electronics engineers(IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, evolved UTRA(E-UTRA), and so on. IEEE 802.16m is an evolved version of IEEE 802.16eand provides backward compatibility with a system based on the IEEE802.16e. The UTRA is part of a universal mobile telecommunication system(UMTS). 3rd generation partnership project (3GPP) long term evolution(LTE) is part of an evolved UMTS (E-UMTS) using the E-UTRA. The 3GPP LTEuses the OFDMA in a downlink and uses the SC-FDMA in an uplink.LTE-advanced (LTE-A) is an evolution of the LTE.

5G NR is a successive technology of LTE-A corresponding to a newClean-slate type mobile communication system having the characteristicsof high performance, low latency, high availability, and so on. 5G NRmay use resources of all spectrum available for usage including lowfrequency bands of less than 1 GHz, middle frequency bands ranging from1 GHz to 10 GHz, high frequency (millimeter waves) of 24 GHz or more,and so on.

For clarity in the description, the following description will mostlyfocus on LTE-A or 5G NR. However, technical features according to anembodiment of the present disclosure will not be limited only to this.

FIG. 2 shows a structure of an NR system, based on an embodiment of thepresent disclosure. The embodiment of FIG. 2 may be combined withvarious embodiments of the present disclosure.

Referring to FIG. 2 , a next generation-radio access network (NG-RAN)may include a BS 20 providing a UE 10 with a user plane and controlplane protocol termination. For example, the BS 20 may include a nextgeneration-Node B (gNB) and/or an evolved-NodeB (eNB). For example, theUE 10 may be fixed or mobile and may be referred to as other terms, suchas a mobile station (MS), a user terminal (UT), a subscriber station(SS), a mobile terminal (MT), wireless device, and so on. For example,the BS may be referred to as a fixed station which communicates with theUE 10 and may be referred to as other terms, such as a base transceiversystem (BTS), an access point (AP), and so on.

The embodiment of FIG. 2 exemplifies a case where only the gNB isincluded. The BSs 20 may be connected to one another via Xn interface.The BS 20 may be connected to one another via 5th generation (5G) corenetwork (5GC) and NG interface. More specifically, the BSs 20 may beconnected to an access and mobility management function (AMF) 30 viaNG-C interface, and may be connected to a user plane function (UPF) 30via NG-U interface.

FIG. 3 shows a functional division between an NG-RAN and a 5GC, based onan embodiment of the present disclosure. The embodiment of FIG. 3 may becombined with various embodiments of the present disclosure.

Referring to FIG. 3 , the gNB may provide functions, such as Inter CellRadio Resource Management (RRM), Radio Bearer (RB) control, ConnectionMobility Control, Radio Admission Control, Measurement Configuration &Provision, Dynamic Resource Allocation, and so on. An AMF may providefunctions, such as Non Access Stratum (NAS) security, idle statemobility processing, and so on. A UPF may provide functions, such asMobility Anchoring, Protocol Data Unit (PDU) processing, and so on. ASession Management Function (SMF) may provide functions, such as userequipment (UE) Internet Protocol (IP) address allocation, PDU sessioncontrol, and so on.

Layers of a radio interface protocol between the UE and the network canbe classified into a first layer (L1), a second layer (L2), and a thirdlayer (L3) based on the lower three layers of the open systeminterconnection (OSI) model that is well-known in the communicationsystem. Among them, a physical (PHY) layer belonging to the first layerprovides an information transfer service by using a physical channel,and a radio resource control (RRC) layer belonging to the third layerserves to control a radio resource between the UE and the network. Forthis, the RRC layer exchanges an RRC message between the UE and the BS.

FIG. 4 shows a radio protocol architecture, based on an embodiment ofthe present disclosure. The embodiment of FIG. 4 may be combined withvarious embodiments of the present disclosure. Specifically, FIG. 4(a)shows a radio protocol architecture for a user plane, and FIG. 4(b)shows a radio protocol architecture for a control plane. The user planecorresponds to a protocol stack for user data transmission, and thecontrol plane corresponds to a protocol stack for control signaltransmission.

Referring to FIG. 4 , a physical layer provides an upper layer with aninformation transfer service through a physical channel. The physicallayer is connected to a medium access control (MAC) layer which is anupper layer of the physical layer through a transport channel. Data istransferred between the MAC layer and the physical layer through thetransport channel. The transport channel is classified according to howand with what characteristics data is transmitted through a radiointerface.

Between different physical layers, i.e., a physical layer of atransmitter and a physical layer of a receiver, data are transferredthrough the physical channel. The physical channel is modulated using anorthogonal frequency division multiplexing (OFDM) scheme, and utilizestime and frequency as a radio resource.

The MAC layer provides services to a radio link control (RLC) layer,which is a higher layer of the MAC layer, via a logical channel. The MAClayer provides a function of mapping multiple logical channels tomultiple transport channels. The MAC layer also provides a function oflogical channel multiplexing by mapping multiple logical channels to asingle transport channel. The MAC layer provides data transfer servicesover logical channels.

The RLC layer performs concatenation, segmentation, and reassembly ofRadio Link Control Service Data Unit (RLC SDU). In order to ensurediverse quality of service (QoS) required by a radio bearer (RB), theRLC layer provides three types of operation modes, i.e., a transparentmode (TM), an unacknowledged mode (UM), and an acknowledged mode (AM).An AM RLC provides error correction through an automatic repeat request(ARQ).

A radio resource control (RRC) layer is defined only in the controlplane. The RRC layer serves to control the logical channel, thetransport channel, and the physical channel in association withconfiguration, reconfiguration and release of RBs. The RB is a logicalpath provided by the first layer (i.e., the physical layer or the PHYlayer) and the second layer (i.e., the MAC layer, the RLC layer, and thepacket data convergence protocol (PDCP) layer) for data delivery betweenthe UE and the network.

Functions of a packet data convergence protocol (PDCP) layer in the userplane include user data delivery, header compression, and ciphering.Functions of a PDCP layer in the control plane include control-planedata delivery and ciphering/integrity protection.

A service data adaptation protocol (SDAP) layer is defined only in auser plane. The SDAP layer performs mapping between a Quality of Service(QoS) flow and a data radio bearer (DRB) and QoS flow ID (QFI) markingin both DL and UL packets.

The configuration of the RB implies a process for specifying a radioprotocol layer and channel properties to provide a particular serviceand for determining respective detailed parameters and operations. TheRB can be classified into two types, i.e., a signaling RB (SRB) and adata RB (DRB). The SRB is used as a path for transmitting an RRC messagein the control plane. The DRB is used as a path for transmitting userdata in the user plane.

When an RRC connection is established between an RRC layer of the UE andan RRC layer of the E-UTRAN, the UE is in an RRC_CONNECTED state, and,otherwise, the UE may be in an RRC_IDLE state. In case of the NR, anRRC_INACTIVE state is additionally defined, and a UE being in theRRC_INACTIVE state may maintain its connection with a core networkwhereas its connection with the BS is released.

Data is transmitted from the network to the UE through a downlinktransport channel. Examples of the downlink transport channel include abroadcast channel (BCH) for transmitting system information and adownlink-shared channel (SCH) for transmitting user traffic or controlmessages. Traffic of downlink multicast or broadcast services or thecontrol messages can be transmitted on the downlink-SCH or an additionaldownlink multicast channel (MCH). Data is transmitted from the UE to thenetwork through an uplink transport channel. Examples of the uplinktransport channel include a random access channel (RACH) fortransmitting an initial control message and an uplink SCH fortransmitting user traffic or control messages.

Examples of logical channels belonging to a higher channel of thetransport channel and mapped onto the transport channels include abroadcast channel (BCCH), a paging control channel (PCCH), a commoncontrol channel (CCCH), a multicast control channel (MCCH), a multicasttraffic channel (MTCH), etc.

The physical channel includes several OFDM symbols in a time domain andseveral sub-carriers in a frequency domain. One sub-frame includes aplurality of OFDM symbols in the time domain. A resource block is a unitof resource allocation, and consists of a plurality of OFDM symbols anda plurality of sub-carriers. Further, each subframe may use specificsub-carriers of specific OFDM symbols (e.g., a first OFDM symbol) of acorresponding subframe for a physical downlink control channel (PDCCH),i.e., an L1/L2 control channel. A transmission time interval (TTI) is aunit time of subframe transmission.

FIG. 5 shows a structure of an NR system, based on an embodiment of thepresent disclosure. The embodiment of FIG. 5 may be combined withvarious embodiments of the present disclosure.

Referring to FIG. 5 , in the NR, a radio frame may be used forperforming uplink and downlink transmission. A radio frame has a lengthof 10 ms and may be defined to be configured of two half-frames (HFs). Ahalf-frame may include five lms subframes (SFs). A subframe (SF) may bedivided into one or more slots, and the number of slots within asubframe may be determined based on subcarrier spacing (SCS). Each slotmay include 12 or 14 OFDM(A) symbols according to a cyclic prefix (CP).

In case of using a normal CP, each slot may include 14 symbols. In caseof using an extended CP, each slot may include 12 symbols. Herein, asymbol may include an OFDM symbol (or CP-OFDM symbol) and a SingleCarrier-FDMA (SC-FDMA) symbol (or Discrete Fourier Transform-spread-OFDM(DFT-s-OFDM) symbol).

Table 1 shown below represents an example of a number of symbols perslot (N^(slot) _(symb)), a number slots per frame (N^(frame,u) _(slot)),and a number of slots per subframe (N^(subframe,u) _(slot)) based on anSCS configuration (u), in a case where a normal CP is used.

TABLE 1 SCS (15*2^(u)) N^(slot) _(symb) N^(frame, u) _(slot)N^(subframe, u) _(slot) 15 KHz (u = 0) 14 10 1 30 KHz (u = 1) 14 20 2 60KHz (u = 2) 14 40 4 120 KHz (u = 3) 14 80 8 240 KHz (u = 4) 14 160 16

Table 2 shows an example of a number of symbols per slot, a number ofslots per frame, and a number of slots per subframe based on the SCS, ina case where an extended CP is used.

TABLE 2 SCS (15*2^(u)) N^(slot) _(symb) N^(frame, u) _(slot)N^(subframe, u) _(slot) 60 KHz (u = 2) 12 40 4

In an NR system, OFDM(A) numerologies (e.g., SCS, CP length, and so on)between multiple cells being integrate to one UE may be differentlyconfigured. Accordingly, a (absolute time) duration (or section) of atime resource (e.g., subframe, slot or TTI) (collectively referred to asa time unit (TU) for simplicity) being configured of the same number ofsymbols may be differently configured in the integrated cells.

In the NR, multiple numerologies or SCSs for supporting diverse 5Gservices may be supported. For example, in case an SCS is 15 kHz, a widearea of the conventional cellular bands may be supported, and, in casean SCS is 30 kHz/60 kHz a dense-urban, lower latency, wider carrierbandwidth may be supported. In case the SCS is 60 kHz or higher, abandwidth that is greater than 24.25 GHz may be used in order toovercome phase noise.

An NR frequency band may be defined as two different types of frequencyranges. The two different types of frequency ranges may be FR1 and FR2.The values of the frequency ranges may be changed (or varied), and, forexample, the two different types of frequency ranges may be as shownbelow in Table 3. Among the frequency ranges that are used in an NRsystem, FR1 may mean a “sub 6 GHz range”, and FR2 may mean an “above 6GHz range” and may also be referred to as a millimeter wave (mmW).

TABLE 3 Frequency Range Corresponding Subcarrier Spacing designationfrequency range (SCS) FR1  450 MHz-6000 MHz 15, 30, 60 kHz FR2 24250MHz-52600 MHz 60, 120, 240 kHz 

As described above, the values of the frequency ranges in the NR systemmay be changed (or varied). For example, as shown below in Table 4, FR1may include a band within a range of 410 MHz to 7125 MHz. Morespecifically, FR1 may include a frequency band of 6 GHz (or 5850, 5900,5925 MHz, and so on) and higher. For example, a frequency band of 6 GHz(or 5850, 5900, 5925 MHz, and so on) and higher being included in FR1mat include an unlicensed band. The unlicensed band may be used fordiverse purposes, e.g., the unlicensed band for vehicle-specificcommunication (e.g., automated driving).

TABLE 4 Frequency Range Corresponding Subcarrier Spacing designationfrequency range (SCS) FR1  410 MHz-7125 MHz 15, 30, 60 kHz FR2 24250MHz-52600 MHz 60, 120, 240 kHz 

FIG. 6 shows a structure of a slot of an NR frame, based on anembodiment of the present disclosure. The embodiment of FIG. 6 may becombined with various embodiments of the present disclosure.

Referring to FIG. 6 , a slot includes a plurality of symbols in a timedomain. For example, in case of a normal CP, one slot may include 14symbols. However, in case of an extended CP, one slot may include 12symbols. Alternatively, in case of a normal CP, one slot may include 7symbols. However, in case of an extended CP, one slot may include 6symbols.

A carrier includes a plurality of subcarriers in a frequency domain. AResource Block (RB) may be defined as a plurality of consecutivesubcarriers (e.g., 12 subcarriers) in the frequency domain. A BandwidthPart (BWP) may be defined as a plurality of consecutive (Physical)Resource Blocks ((P)RBs) in the frequency domain, and the BWP maycorrespond to one numerology (e.g., SCS, CP length, and so on). Acarrier may include a maximum of N number BWPs (e.g., 5 BWPs). Datacommunication may be performed via an activated BWP. Each element may bereferred to as a Resource Element (RE) within a resource grid and onecomplex symbol may be mapped to each element.

Meanwhile, a radio interface between a UE and another UE or a radiointerface between the UE and a network may consist of an L1 layer, an L2layer, and an L3 layer. In various embodiments of the presentdisclosure, the L1 layer may imply a physical layer. In addition, forexample, the L2 layer may imply at least one of a MAC layer, an RLClayer, a PDCP layer, and an SDAP layer. In addition, for example, the L3layer may imply an RRC layer.

Hereinafter, a bandwidth part (BWP) and a carrier will be described.

The BWP may be a set of consecutive physical resource blocks (PRBs) in agiven numerology. The PRB may be selected from consecutive sub-sets ofcommon resource blocks (CRBs) for the given numerology on a givencarrier.

When using bandwidth adaptation (BA), a reception bandwidth andtransmission bandwidth of a UE are not necessarily as large as abandwidth of a cell, and the reception bandwidth and transmissionbandwidth of the BS may be adjusted. For example, a network/BS mayinform the UE of bandwidth adjustment. For example, the UE receiveinformation/configuration for bandwidth adjustment from the network/BS.In this case, the UE may perform bandwidth adjustment based on thereceived information/configuration. For example, the bandwidthadjustment may include an increase/decrease of the bandwidth, a positionchange of the bandwidth, or a change in subcarrier spacing of thebandwidth.

For example, the bandwidth may be decreased during a period in whichactivity is low to save power. For example, the position of thebandwidth may move in a frequency domain. For example, the position ofthe bandwidth may move in the frequency domain to increase schedulingflexibility. For example, the subcarrier spacing of the bandwidth may bechanged. For example, the subcarrier spacing of the bandwidth may bechanged to allow a different service. A subset of a total cell bandwidthof a cell may be called a bandwidth part (BWP). The BA may be performedwhen the BS/network configures the BWP to the UE and the BS/networkinforms the UE of the BWP currently in an active state among theconfigured BWPs. For example, the BWP may be at least any one of anactive BWP, an initial BWP, and/or a default BWP. For example, the UEmay not monitor downlink radio link quality in a DL BWP other than anactive DL BWP on a primary cell (PCell). For example, the UE may notreceive PDCCH, physical downlink shared channel (PDSCH), or channelstate information-reference signal (CSI-RS) (excluding RRM) outside theactive DL BWP. For example, the UE may not trigger a channel stateinformation (CSI) report for the inactive DL BWP. For example, the UEmay not transmit physical uplink control channel (PUCCH) or physicaluplink shared channel (PUSCH) outside an active UL BWP. For example, ina downlink case, the initial BWP may be given as a consecutive RB setfor a remaining minimum system information (RMSI) control resource set(CORESET) (configured by physical broadcast channel (PBCH)). Forexample, in an uplink case, the initial BWP may be given by systeminformation block (SIB) for a random access procedure. For example, thedefault BWP may be configured by a higher layer. For example, an initialvalue of the default BWP may be an initial DL BWP. For energy saving, ifthe UE fails to detect downlink control information (DCI) during aspecific period, the UE may switch the active BWP of the UE to thedefault BWP.

Meanwhile, the BWP may be defined for SL. The same SL BWP may be used intransmission and reception. For example, a transmitting UE may transmitn SL channel or a SL signal on a specific BWP, and a receiving UE mayreceive the SL channel or the SL signal on the specific BWP. In alicensed carrier, the SL BWP may be defined separately from a Uu BWP,and the SL BWP may have configuration signaling separate from the UuBWP. For example, the UE may receive a configuration for the SL BWP fromthe BS/network. The SL BWP may be (pre-)configured in a carrier withrespect to an out-of-coverage NR V2X UE and an RRC_IDLE UE. For the UEin the RRC_CONNECTED mode, at least one SL BWP may be activated in thecarrier.

FIG. 7 shows an example of a BWP, based on an embodiment of the presentdisclosure. The embodiment of FIG. 7 may be combined with variousembodiments of the present disclosure. It is assumed in the embodimentof FIG. 7 that the number of BWPs is 3.

Referring to FIG. 7 , a common resource block (CRB) may be a carrierresource block numbered from one end of a carrier band to the other endthereof. In addition, the PRB may be a resource block numbered withineach BWP. A point A may indicate a common reference point for a resourceblock grid.

The BWP may be configured by a point A, an offset N^(start) _(BWP) fromthe point A, and a bandwidth N^(size) _(BWP). For example, the point Amay be an external reference point of a PRB of a carrier in which asubcarrier 0 of all numerologies (e.g., all numerologies supported by anetwork on that carrier) is aligned. For example, the offset may be aPRB interval between a lowest subcarrier and the point A in a givennumerology. For example, the bandwidth may be the number of PRBs in thegiven numerology.

Hereinafter, V2X or SL communication will be described.

FIG. 8 shows a radio protocol architecture for a SL communication, basedon an embodiment of the present disclosure. The embodiment of FIG. 8 maybe combined with various embodiments of the present disclosure. Morespecifically, FIG. 8(a) shows a user plane protocol stack, and FIG. 8(b)shows a control plane protocol stack.

Hereinafter, a sidelink synchronization signal (SLSS) andsynchronization information will be described.

The SLSS may include a primary sidelink synchronization signal (PSSS)and a secondary sidelink synchronization signal (SSSS), as a SL-specificsequence. The PSSS may be referred to as a sidelink primarysynchronization signal (S-PSS), and the SSSS may be referred to as asidelink secondary synchronization signal (S-SSS). For example,length-127 M-sequences may be used for the S-PSS, and length-127 goldsequences may be used for the S-SSS. For example, a UE may use the S-PSSfor initial signal detection and for synchronization acquisition. Forexample, the UE may use the S-PSS and the S-SSS for acquisition ofdetailed synchronization and for detection of a synchronization signalID.

A physical sidelink broadcast channel (PSBCH) may be a (broadcast)channel for transmitting default (system) information which must befirst known by the UE before SL signal transmission/reception. Forexample, the default information may be information related to SLSS, aduplex mode (DM), a time division duplex (TDD) uplink/downlink (UL/DL)configuration, information related to a resource pool, a type of anapplication related to the SLSS, a subframe offset, broadcastinformation, or the like. For example, for evaluation of PSBCHperformance, in NR V2X, a payload size of the PSBCH may be 56 bitsincluding 24-bit cyclic redundancy check (CRC).

The S-PSS, the S-SSS, and the PSBCH may be included in a block format(e.g., SL synchronization signal (SS)/PSBCH block, hereinafter,sidelink-synchronization signal block (S-SSB)) supporting periodicaltransmission. The S-SSB may have the same numerology (i.e., SCS and CPlength) as a physical sidelink control channel (PSCCH)/physical sidelinkshared channel (PSSCH) in a carrier, and a transmission bandwidth mayexist within a (pre-)configured sidelink (SL) BWP. For example, theS-SSB may have a bandwidth of 11 resource blocks (RBs). For example, thePSBCH may exist across 11 RBs. In addition, a frequency position of theS-SSB may be (pre-)configured. Accordingly, the UE does not have toperform hypothesis detection at frequency to discover the S-SSB in thecarrier.

FIG. 9 shows a UE performing V2X or SL communication, based on anembodiment of the present disclosure. The embodiment of FIG. 9 may becombined with various embodiments of the present disclosure.

Referring to FIG. 9 , in V2X or SL communication, the term ‘UE’ maygenerally imply a UE of a user. However, if a network equipment such asa BS transmits/receives a signal according to a communication schemebetween UEs, the BS may also be regarded as a sort of the UE. Forexample, a UE 1 may be a first apparatus 100, and a UE 2 may be a secondapparatus 200.

For example, the UE 1 may select a resource unit corresponding to aspecific resource in a resource pool which implies a set of series ofresources. In addition, the UE 1 may transmit a SL signal by using theresource unit. For example, a resource pool in which the UE 1 is capableof transmitting a signal may be configured to the UE 2 which is areceiving UE, and the signal of the UE 1 may be detected in the resourcepool.

Herein, if the UE 1 is within a connectivity range of the BS, the BS mayinform the UE 1 of the resource pool. Otherwise, if the UE 1 is out ofthe connectivity range of the BS, another UE may inform the UE 1 of theresource pool, or the UE 1 may use a pre-configured resource pool.

In general, the resource pool may be configured in unit of a pluralityof resources, and each UE may select a unit of one or a plurality ofresources to use it in SL signal transmission thereof.

Hereinafter, resource allocation in SL will be described.

FIG. 10 shows a procedure of performing V2X or SL communication by a UEbased on a transmission mode, based on an embodiment of the presentdisclosure. The embodiment of FIG. 10 may be combined with variousembodiments of the present disclosure. In various embodiments of thepresent disclosure, the transmission mode may be called a mode or aresource allocation mode. Hereinafter, for convenience of explanation,in LTE, the transmission mode may be called an LTE transmission mode. InNR, the transmission mode may be called an NR resource allocation mode.

For example, FIG. 10(a) shows a UE operation related to an LTEtransmission mode 1 or an LTE transmission mode 3. Alternatively, forexample, FIG. 10(a) shows a UE operation related to an NR resourceallocation mode 1. For example, the LTE transmission mode 1 may beapplied to general SL communication, and the LTE transmission mode 3 maybe applied to V2X communication.

For example, FIG. 10(b) shows a UE operation related to an LTEtransmission mode 2 or an LTE transmission mode 4. Alternatively, forexample, FIG. 10(b) shows a UE operation related to an NR resourceallocation mode 2.

Referring to FIG. 10(a), in the LTE transmission mode 1, the LTEtransmission mode 3, or the NR resource allocation mode 1, a BS mayschedule a SL resource to be used by the UE for SL transmission. Forexample, the BS may perform resource scheduling to a UE 1 through aPDCCH (more specifically, downlink control information (DCI)), and theUE 1 may perform V2X or SL communication with respect to a UE 2according to the resource scheduling. For example, the UE 1 may transmita sidelink control information (SCI) to the UE 2 through a physicalsidelink control channel (PSCCH), and thereafter transmit data based onthe SCI to the UE 2 through a physical sidelink shared channel (PSSCH).

Referring to FIG. 10(b), in the LTE transmission mode 2, the LTEtransmission mode 4, or the NR resource allocation mode 2, the UE maydetermine a SL transmission resource within a SL resource configured bya BS/network or a pre-configured SL resource. For example, theconfigured SL resource or the pre-configured SL resource may be aresource pool. For example, the UE may autonomously select or schedule aresource for SL transmission. For example, the UE may perform SLcommunication by autonomously selecting a resource within a configuredresource pool. For example, the UE may autonomously select a resourcewithin a selective window by performing a sensing and resource(re)selection procedure. For example, the sensing may be performed inunit of subchannels. In addition, the UE 1 which has autonomouslyselected the resource within the resource pool may transmit the SCI tothe UE 2 through a PSCCH, and thereafter may transmit data based on theSCI to the UE 2 through a PSSCH.

FIG. 11 shows three cast types, based on an embodiment of the presentdisclosure. The embodiment of FIG. 11 may be combined with variousembodiments of the present disclosure. Specifically, FIG. 11(a) showsbroadcast-type SL communication, FIG. 11(b) shows unicast type-SLcommunication, and FIG. 11(c) shows groupcast-type SL communication. Incase of the unicast-type SL communication, a UE may perform one-to-onecommunication with respect to another UE. In case of the groupcast-typeSL transmission, the UE may perform SL communication with respect to oneor more UEs in a group to which the UE belongs. In various embodimentsof the present disclosure, SL groupcast communication may be replacedwith SL multicast communication, SL one-to-many communication, or thelike.

Hereinafter, a hybrid automatic repeat request (HARQ) procedure will bedescribed.

An error compensation scheme is used to secure communicationreliability. Examples of the error compensation scheme may include aforward error correction (FEC) scheme and an automatic repeat request(ARQ) scheme. In the FEC scheme, errors in a receiving end are correctedby attaching an extra error correction code to information bits. The FECscheme has an advantage in that time delay is small and no informationis additionally exchanged between a transmitting end and the receivingend but also has a disadvantage in that system efficiency deterioratesin a good channel environment. The ARQ scheme has an advantage in thattransmission reliability can be increased but also has a disadvantage inthat a time delay occurs and system efficiency deteriorates in a poorchannel environment.

A hybrid automatic repeat request (HARQ) scheme is a combination of theFEC scheme and the ARQ scheme. In the HARQ scheme, it is determinedwhether an unrecoverable error is included in data received by aphysical layer, and retransmission is requested upon detecting theerror, thereby improving performance.

In case of SL unicast and groupcast, HARQ feedback and HARQ combining inthe physical layer may be supported. For example, when a receiving UEoperates in a resource allocation mode 1 or 2, the receiving UE mayreceive the PSSCH from a transmitting UE, and the receiving UE maytransmit HARQ feedback for the PSSCH to the transmitting UE by using asidelink feedback control information (SFCI) format through a physicalsidelink feedback channel (PSFCH).

For example, the SL HARQ feedback may be enabled for unicast. In thiscase, in a non-code block group (non-CBG) operation, if the receiving UEdecodes a PSCCH of which a target is the receiving UE and if thereceiving UE successfully decodes a transport block related to thePSCCH, the receiving UE may generate HARQ-ACK. In addition, thereceiving UE may transmit the HARQ-ACK to the transmitting UE.Otherwise, if the receiving UE cannot successfully decode the transportblock after decoding the PSCCH of which the target is the receiving UE,the receiving UE may generate the HARQ-NACK. In addition, the receivingUE may transmit HARQ-NACK to the transmitting UE.

For example, the SL HARQ feedback may be enabled for groupcast. Forexample, in the non-CBG operation, two HARQ feedback options may besupported for groupcast.

(1) Groupcast option 1: After the receiving UE decodes the PSCCH ofwhich the target is the receiving UE, if the receiving UE fails indecoding of a transport block related to the PSCCH, the receiving UE maytransmit HARQ-NACK to the transmitting UE through a PSFCH. Otherwise, ifthe receiving UE decodes the PSCCH of which the target is the receivingUE and if the receiving UE successfully decodes the transport blockrelated to the PSCCH, the receiving UE may not transmit the HARQ-ACK tothe transmitting UE.

(2) Groupcast option 2: After the receiving UE decodes the PSCCH ofwhich the target is the receiving UE, if the receiving UE fails indecoding of the transport block related to the PSCCH, the receiving UEmay transmit HARQ-NACK to the transmitting UE through the PSFCH. Inaddition, if the receiving UE decodes the PSCCH of which the target isthe receiving UE and if the receiving UE successfully decodes thetransport block related to the PSCCH, the receiving UE may transmit theHARQ-ACK to the transmitting UE through the PSFCH.

For example, if the groupcast option 1 is used in the SL HARQ feedback,all UEs performing groupcast communication may share a PSFCH resource.For example, UEs belonging to the same group may transmit HARQ feedbackby using the same PSFCH resource.

For example, if the groupcast option 2 is used in the SL HARQ feedback,each UE performing groupcast communication may use a different PSFCHresource for HARQ feedback transmission. For example, UEs belonging tothe same group may transmit HARQ feedback by using different PSFCHresources.

For example, when the SL HARQ feedback is enabled for groupcast, thereceiving UE may determine whether to transmit the HARQ feedback to thetransmitting UE based on a transmission-reception (TX-RX) distanceand/or RSRP.

For example, in the groupcast option 1, in case of the TX-RXdistance-based HARQ feedback, if the TX-RX distance is less than orequal to a communication range requirement, the receiving UE maytransmit HARQ feedback for the PSSCH to the transmitting UE. Otherwise,if the TX-RX distance is greater than the communication rangerequirement, the receiving UE may not transmit the HARQ feedback for thePSSCH to the transmitting UE. For example, the transmitting UE mayinform the receiving UE of a location of the transmitting UE through SCIrelated to the PSSCH. For example, the SCI related to the PSSCH may besecond SCI. For example, the receiving UE may estimate or obtain theTX-RX distance based on a location of the receiving UE and the locationof the transmitting UE. For example, the receiving UE may decode the SCIrelated to the PSSCH and thus may know the communication rangerequirement used in the PSSCH.

For example, in case of the resource allocation mode 1, a time (offset)between the PSFCH and the PSSCH may be configured or pre-configured. Incase of unicast and groupcast, if retransmission is necessary on SL,this may be indicated to a BS by an in-coverage UE which uses the PUCCH.The transmitting UE may transmit an indication to a serving BS of thetransmitting UE in a form of scheduling request (SR)/buffer statusreport (BSR), not a form of HARQ ACK/NACK. In addition, even if the BSdoes not receive the indication, the BS may schedule an SLretransmission resource to the UE. For example, in case of the resourceallocation mode 2, a time (offset) between the PSFCH and the PSSCH maybe configured or pre-configured.

For example, from a perspective of UE transmission in a carrier, TDMbetween the PSCCH/PSSCH and the PSFCH may be allowed for a PSFCH formatfor SL in a slot. For example, a sequence-based PSFCH format having asingle symbol may be supported. Herein, the single symbol may not an AGCduration. For example, the sequence-based PSFCH format may be applied tounicast and groupcast.

For example, in a slot related to a resource pool, a PSFCH resource maybe configured periodically as N slot durations, or may bepre-configured. For example, N may be configured as one or more valuesgreater than or equal to 1. For example, N may be 1, 2, or 4. Forexample, HARQ feedback for transmission in a specific resource pool maybe transmitted only through a PSFCH on the specific resource pool.

For example, if the transmitting UE transmits the PSSCH to the receivingUE across a slot #X to a slot #N, the receiving UE may transmit HARQfeedback for the PSSCH to the transmitting UE in a slot #(N+A). Forexample, the slot #(N+A) may include a PSFCH resource. Herein, forexample, A may be a smallest integer greater than or equal to K. Forexample, K may be the number of logical slots. In this case, K may bethe number of slots in a resource pool. Alternatively, for example, Kmay be the number of physical slots. In this case, K may be the numberof slots inside or outside the resource pool.

For example, if the receiving UE transmits HARQ feedback on a PSFCHresource in response to one PSSCH transmitted by the transmitting UE tothe receiving UE, the receiving UE may determine a frequency domainand/or code domain of the PSFCH resource based on an implicit mechanismin a configured resource pool. For example, the receiving UE maydetermine the frequency domain and/or code domain of the PSFCH resource,based on at least one of a slot index related to PSCCH/PSSCH/PSFCH, asub-channel related to PSCCH/PSSCH, and/or an identifier for identifyingeach receiving UE in a group for HARQ feedback based on the groupcastoption 2. Additionally/alternatively, for example, the receiving UE maydetermine the frequency domain and/or code domain of the PSFCH resource,based on at least one of SL RSRP, SINR, L1 source ID, and/or locationinformation.

For example, if HARQ feedback transmission through the PSFCH of the UEand HARQ feedback reception through the PSFCH overlap, the UE may selectany one of HARQ feedback transmission through the PSFCH and HARQfeedback reception through the PSFCH based on a priority rule. Forexample, the priority rule may be based on at least priority indicationof the related PSCCH/PSSCH.

For example, if HARQ feedback transmission of a UE through a PSFCH for aplurality of UEs overlaps, the UE may select specific HARQ feedbacktransmission based on the priority rule. For example, the priority rulemay be based on at least priority indication of the related PSCCH/PSSCH.

Meanwhile, in the present disclosure, for example, a transmitting UE (TXUE) may be a UE which transmits data to a (target) receiving UE (RX UE).For example, the TX UE may be a UE which performs PSCCH transmissionand/or PSSCH transmission. Additionally/alternatively, for example, theTX UE may be a UE which transmits SL CSI-RS(s) and/or a SL CSI reportrequest indicator to the (target) RX UE. Additionally/alternatively, forexample, the TX UE may be a UE which transmits a (control) channel(e.g., PSCCH, PSSCH, etc.) and/or reference signal(s) on the (control)channel (e.g., DM-RS, CSI-RS, etc.), to be used for a SL RLM operationand/or a SL RLF operation of the (target) RX UE.

Meanwhile, in the present disclosure, for example, a receiving UE (RXUE) may be a UE which transmits SL HARQ feedback to a transmitting UE(TX UE) based on whether decoding of data received from the TX UE issuccessful and/or whether detection/decoding of a PSCCH (related toPSSCH scheduling) transmitted by the TX UE is successful.Additionally/alternatively, for example, the RX UE may be a UE whichperforms SL CSI transmission to the TX UE based on SL CSI-RS(s) and/or aSL CSI report request indicator received from the TX UE.Additionally/alternatively, for example, the RX UE is a UE whichtransmits a SL (L1) RSRP measurement value, to the TX UE, measured basedon (pre-defined) reference signal(s) and/or a SL (L1) RSRP reportrequest indicator received from the TX UE. Additionally/alternatively,for example, the RX UE may be a UE which transmits data of the RX UE tothe TX UE. Additionally/alternatively, for example, the RX UE may be aUE which performs a SL RLM operation and/or a SL RLF operation based ona (pre-configured) (control) channel and/or reference signal(s) on the(control) channel received from the TX UE.

Meanwhile, in the present disclosure, for example, in case the RX UEtransmits SL HARQ feedback information for a PSSCH and/or a PSCCHreceived from the TX UE, the following options or some of the followingoptions may be considered. Herein, for example, the following options orsome of the following options may be limitedly applied only if the RX UEsuccessfully decodes/detects a PSCCH scheduling a PSSCH.

(1) groupcast HARQ feedback option 1: NACK information may betransmitted to the TX UE only if the RX UE fails to decode/receive thePSSCH received from the TX UE.

(2) groupcast HARQ feedback option 2: If the RX UE succeeds indecoding/receiving the PSSCH received from the TX UE, ACK informationmay be transmitted to the TX UE, and if the RX UE fails todecode/receive the PSSCH, NACK information may be transmitted to the TXUE.

Meanwhile, in the present disclosure, for example, the TX UE maytransmit the following information or some of the following informationto the RX UE through SCI(s). Herein, for example, the TX UE may transmitsome or all of the following information to the RX UE through a firstSCI and/or a second SCI.

PSSCH (and/or PSCCH) related resource allocation information (e.g., thelocation/number of time/frequency resources, resource reservationinformation (e.g., period))

SL CSI report request indicator or SL (L1) RSRP (and/or SL (L1) RSRQand/or SL (L1) RSSI) report request indicator

SL CSI transmission indicator (or SL (L1) RSRP (and/or SL (L1) RSRQand/or SL (L1) RSSI) information transmission indicator) (on a PSSCH)

MCS information

TX power information

L1 destination ID information and/or L1 source ID information

SL HARQ process ID information

NDI information

RV information

(Transmission traffic/packet related) QoS information (e.g., priorityinformation)

SL CSI-RS transmission indicator or information on the number of antennaports for (transmitting) SL CSI-RS

TX UE location information or location (or distance range) informationof the target RX UE (for which SL HARQ feedback is requested)

Reference signal (e.g., DM-RS, etc.) information related to decoding(and/or channel estimation) of data transmitted through a PSSCH. Forexample, information related to a pattern of (time-frequency) mappingresources of DM-RS(s), RANK information, antenna port index information,information on the number of antenna ports, etc.

Meanwhile, in the present disclosure, for example, since the TX UE maytransmit a SCI, a first SCI and/or a second SCI to the RX UE through aPSCCH, the PSCCH may be replaced/substituted with the SCI and/or thefirst SCI and/or the second SCI. Additionally/alternatively, the SCI maybe replaced/substituted with the PSCCH and/or the first SCI and/or thesecond SCI. Additionally/alternatively, for example, since the TX UE maytransmit a second SCI to the RX UE through a PSSCH, the PSSCH may bereplaced/substituted with the second SCI.

Meanwhile, in the present disclosure, for example, if SCI configurationfields are divided into two groups in consideration of a (relatively)high SCI payload size, the first SCI including a first SCI configurationfield group may be referred to as a 1^(st) SCI, and the second SCIincluding a second SCI configuration field group may be referred to as a2^(nd) SCI. Also, for example, the 1^(st) SCI may be transmitted to thereceiving UE through a PSCCH. Also, for example, the 2^(nd) SCI may betransmitted to the receiving UE through a (independent) PSCCH or may bepiggybacked and transmitted together with data through a PSSCH.

Meanwhile, in the present disclosure, for example, the term“configure/configured” or the term “define/defined” may refer to(pre)configuration from a base station or a network (through pre-definedsignaling (e.g., SIB, MAC, RRC, etc.)) (for each resource pool).

Meanwhile, in the present disclosure, for example, a packet or a trafficmay be replaced/substituted with a transport block (TB) or a mediumaccess control (MAC) packet data unit (PDU) based on a transmissionlayer.

Meanwhile, in the present disclosure, for example, an operation of thetransmitting UE to reserve/select/determine retransmission resource(s)may include: an operation of the transmitting UE toreserve/select/determine potential retransmission resource(s) for whichactual use will be determined based on SL HARQ feedback informationreceived from the receiving UE.

Meanwhile, in the present disclosure, SL MODE 1 may refer to a resourceallocation method or a communication method in which a base stationdirectly schedules SL transmission resource(s) for a TX UE throughpre-defined signaling (e.g., DCI or RRC message). For example, SL MODE 2may refer to a resource allocation method or a communication method inwhich a UE independently selects SL transmission resource(s) in aresource pool pre-configured or configured from a base station or anetwork. For example, a UE performing SL communication based on SL MODE1 may be referred to as a MODE 1 UE or MODE 1 TX UE, and a UE performingSL communication based on SL MODE 2 may be referred to as a MODE 2 UE orMODE 2 TX UE.

Meanwhile, in the present disclosure, for example, a dynamic grant (DG)may be replaced/substituted with a configured grant (CG) and/or asemi-persistent scheduling (SPS) grant, or vice versa. For example, theDG may be replaced/substituted with a combination of the CG and the SPSgrant, or vice versa. In the present disclosure, the CG may include atleast one of a configured grant (CG) type 1 and/or a configured grant(CG) type 2. For example, in the CG type 1, a grant may be provided byRRC signaling and may be stored as a configured grant. For example, inthe CG type 2, a grant may be provided by a PDCCH, and may be stored ordeleted as a configured grant based on L1 signaling indicatingactivation or deactivation of the grant.

Meanwhile, in the present disclosure, a channel may bereplaced/substituted with a signal, or vice versa. For example,transmission/reception of a channel may include transmission/receptionof a signal. For example, transmission/reception of a signal may includetransmission/reception of a channel.

Meanwhile, in the present disclosure, cast may be replaced/substitutedwith at least one of unicast, groupcast, and/or broadcast, or viceversa. For example, a cast type may be replaced/substituted with atleast one of unicast, groupcast, and/or broadcast, or vice versa. Forexample, the cast or the cast type may include unicast, groupcast and/orbroadcast.

Meanwhile, in the present disclosure, a resource may bereplaced/substituted with a slot or a symbol, or vice versa. Forexample, the resource may include a slot and/or a symbol.

Meanwhile, in the present disclosure, a priority may bereplaced/substituted with at least one of logical channel prioritization(LCP), latency, reliability, minimum required communication range, PPPP,sidelink radio bearer (SLRB), a QoS profile, a QoS parameter, and/or arequirement, or vice versa.

Meanwhile, in the present disclosure, for example, for convenience ofdescription, a (physical) channel used when a RX UE transmits at leastone of the following information to a TX UE may be referred to as aPSFCH.

SL HARQ feedback, SL CSI, SL (L1) RSRP

Meanwhile, in the present disclosure, a Uu channel may include a ULchannel and/or a DL channel For example, the UL channel may include aPUSCH, a PUCCH, etc. For example, the DL channel may include a PDCCH, aPDSCH, etc. For example, a SL channel may include a PSCCH, a PSSCH, aPSFCH, a PSBCH, etc.

Meanwhile, in the present disclosure, sidelink information may includeat least one of a sidelink message, a sidelink packet, a sidelinkservice, sidelink data, sidelink control information, and/or a sidelinktransport block (TB). For example, sidelink information may betransmitted through a PSSCH and/or a PSCCH.

Meanwhile, in NR SL or NR V2X, HARQ feedback may be supported betweenthe TX UE and the RX UE. Furthermore, the TX UE may report SL HARQfeedback received from the RX UE to the base station. For example, inorder to request the base station to allocate additional(re)transmission resource(s), the TX UE may report SL HARQ feedbackreceived from the RX UE to the base station.

For example, SL HARQ feedback report may be supported as shown in Table5.

TABLE 5 For dynamic grant and configured grant: If the gNB providesPUCCH resources for feedback, the UE reports SL HARQ feedback to thegNB, If the gNB does not provides PUCCH resources for feedback, the UEdoes not report SL HARQ feedback to the gNB.

Referring to Table 5, for example, if the base stationschedules/allocates SL resource(s) to the TX UE through the DG or theCG, the base station may additionally schedule/allocate PUCCHresource(s) related to the SL resource(s) to the TX UE. Alternatively,for example, if the base station schedules/allocates SL resource(s) tothe TX UE through the DG or the CG, the base station may notschedule/allocate PUCCH resource(s) related to the SL resource(s) to theTX UE. For example, if the base station schedules/allocates the PUCCHresource(s) related to the SL resource(s) to the TX UE, the TX UE mayreport SL HARQ feedback received from the RX UE to the base station byusing the PUCCH resource(s). For example, if the base station does notschedule/allocate the PUCCH resource(s) related to the SL resource(s) tothe TX UE, the TX UE may not report SL HARQ feedback received from theRX UE to the base station. For example, the SL resource(s) may includeat least one of PSSCH resource(s), PSCCH resource(s), and/or PSFCHresource(s).

Meanwhile, in NR SL or NR V2X, the TX UE may perform logical channelprioritization (LCP) for obtaining a MAC PDU. In addition, as shown inTable 6, HARQ enable and/or HARQ disable may be included in the LCPrestriction.

TABLE 6 LCP will take HARQ A/N enabled/disabled into account, e.g.packet with HARQ enabled will be multiplexed only with packets with HARQenabled. The logical channel with disabling the HARQ feedback cannot bemultiplexed with a logical channel which enabling the HARQ feedback.

Referring to Table 6, enabling HARQ feedback or disabling HARQ feedbackmay be considered in LCP. For example, in case the TX UE obtains a MACPDU, the TX UE may obtain the MAC PDU by multiplexing only packet(s) forwhich HARQ feedback is enabled. For example, in case the TX UE obtains aMAC PDU, the TX UE may obtain the MAC PDU by multiplexing only logicalchannel(s) configured with HARQ feedback enabled. For example, in casethe TX UE obtains a MAC PDU, the TX UE may obtain the MAC PDU bymultiplexing only packet(s) for which HARQ feedback is disabled. Forexample, in case the TX UE obtains a MAC PDU, the TX UE may obtain theMAC PDU by multiplexing only logical channel(s) configured with HARQfeedback disabled. For example, the TX UE may not obtain a MAC PDU bymultiplexing packet(s) for which HARQ feedback is disabled and packet(s)for which HARQ feedback is enabled. For convenience of description, aMAC PDU including only packet(s) for which HARQ feedback is enabled maybe referred to as a HARQ enable MAC PDU, and a MAC PDU including onlypacket(s) for which HARQ feedback is disabled may be referred to as aHARQ disable MAC PDU. For example, the HARQ enable MAC PDU may includelogical channel(s) configured with HARQ feedback enabled, but it may notinclude logical channel(s) configured with HARQ feedback disabled. Forexample, the HARQ disable MAC PDU may include logical channel(s)configured with HARQ feedback disabled, but it may not include logicalchannel(s) configured with HARQ feedback enabled.

Meanwhile, according to the current NR V2X status, in resourceallocation mode 1, the base station may schedule/allocate SL resource(s)to the TX UE through the DG and/or the CG. For convenience ofdescription, the DG and/or the CG for scheduling/allocating SLresource(s) may be referred to as a SL grant. For example, if the basestation schedules/allocates SL resource(s) to the TX UE through the SLgrant, the TX UE may transmit either a HARQ enable MAC PDU or a HARQdisable MAC PDU to the RX UE by using the SL resource(s). For example,if the base station schedules/allocates SL resource(s) to the TX UEthrough the SL grant, the TX UE may transmit either a HARQ enable MACPDU or a HARQ disable MAC PDU to the RX UE by using the SL resource(s),regardless of whether the base station schedules/allocates PUCCHresource(s) related to the SL resource(s) to the TX UE. That is, sincethere is no HARQ restriction in a specific SL grant, the TX UE may nottransmit only the HARQ enable MAC PDU or may not transmit only the HARQdisable MAC PDU, by using the SL resource(s) allocated through the SLgrant. Thus, for example, if there is a PUCCH resource related to the SLgrant, the TX UE may transmit the HARQ disable MAC PDU to the RX UE byusing the SL resource(s) allocated through the SL grant, and the TX UEmay also transmit SL HARQ feedback to the base station by using thePUCCH resource.

Hereinafter, based on various embodiments of the present disclosure, incase a base station allocates SL resource(s) to a TX UE through a SLgrant, a method for the TX UE to transmit a MAC PDU based on whether aPUCCH resource related to the SL grant exists, and an apparatussupporting the same, will be described.

For example, the base station may schedule/allocate SL resource(s) tothe TX UE through the SL grant (e.g., DCI). For example, the TX UE maytransmit a MAC PDU to the RX UE by using the SL resource(s). Forexample, if the MAC PDU is a HARQ enable MAC PDU, the TX UE may receiveSL HARQ feedback related to the MAC PDU from the RX UE. For example, theTX UE may report SL HARQ feedback to the base station by using the PUCCHresource indicated/informed by the SL grant. Herein, for example,indicating/informing the PUCCH resource by the SL grant may refer tothat the base station indicates/informs, through the SL grant, the TX UEof a specific configuration among PUCCH configuration(s) configured tothe TX UE through RRC signaling. For example, in the case of SLconfigured grant (CG), the base station may configure/allocate a PUCCHresource to the TX UE through RRC signaling. For convenience ofdescription, for example, a case in which the base station allocates SLresource(s) and a PUCCH resource related to the SL resource(s) to the TXUE through the SL grant may be referred to as CASE A. For example, acase in which the base station allocates only SL resource(s) to the TXUE through the SL grant and does not allocate a PUCCH resource relatedto the SL resource(s) to the TX UE may be referred to as CASE B.

1. CASE A

Based on an embodiment of the present disclosure, the base station mayschedule/allocate SL resource(s) and a PUCCH resource related to the SLresource(s) to the TX UE. In this case, the TX UE may transmit a HARQenable MAC PDU and a HARQ disable MAC PDU to the RX UE by using the SLresource(s) allocated from the base station through the SL grant.

For example, if the TX UE transmits the HARQ enable MAC PDU to the RXUE, the TX UE may not successfully transmit the HARQ enable MAC PDU tothe RX UE by using an initial transmission resource and/orretransmission resource(s) scheduled/allocated by the SL grant. In thiscase, the TX UE may transmit HARQ NACK to the base station by using thePUCCH resource related to the resource(s) scheduled/allocated by the SLgrant. Through this, the TX UE may request resource(s) forretransmission of the HARQ enable MAC PDU from the base station.

FIG. 12 shows a procedure for a TX UE to request retransmissionresource(s) in case a base station allocates SL resource(s) and a PUCCHresource to the TX UE, based on an embodiment of the present disclosure.The embodiment of FIG. 12 may be combined with various embodiments ofthe present disclosure.

Referring to FIG. 12 , in step S1210, the base station may transmitinformation related to SL resource(s) and information related to a PUCCHresource to the TX UE. For example, the base station may transmit theinformation related to the SL resource(s) to the TX UE through a SL DG(e.g., DCI). For example, the base station may transmit the informationrelated to the PUCCH resource to the TX UE through the DCI and/or an RRCmessage.

In step S1220, the TX UE may obtain/generate a HARQ disable MAC PDU. Forexample, if the TX UE transmits the HARQ disable MAC PDU to the RX UE,the TX UE may transmit the HARQ disable MAC PDU to the RX UE by using aninitial transmission resource and/or retransmission resource(s)scheduled/allocated by the SL DG. For example, the base station mayschedule/allocate one initial transmission resource and tworetransmission resources to the TX UE through one SL DG. For example,the TX UE may perform one initial transmission and two blindretransmissions for the HARQ disable MAC PDU.

In step S1230, the TX UE may determine that additional retransmission isrequired. In this case, for example, the TX UE may not be able toperform necessary retransmission by using the initial transmissionresource and/or the retransmission resource(s) scheduled by the basestation through one SL DG. Alternatively, for example, the TX UE may notbe able to perform retransmission by the maximum number ofretransmissions by using the initial transmission resource and/or theretransmission resource(s) scheduled by the base station through one SLDG. Alternatively, for example, the TX UE may determine that there is noSL grant available for retransmission.

In the above-described case, in step S1240, the TX UE may transmit HARQNACK to the base station by using the PUCCH resource related toresource(s) scheduled/allocated by the SL DG. Through this, the TX UEmay request resource(s) for retransmission of the HARQ disable MAC PDUfrom the base station. Through this operation, if the TX UE performingblind retransmission for the HARQ disable MAC PDU fails to perform allnecessary retransmissions, the TX UE may request the base station toallocate additional retransmission resource(s) by using the PUCCHresource.

FIG. 13 shows a procedure for a TX UE to request retransmissionresource(s) in case a base station allocates SL resource(s) and a PUCCHresource to the TX UE, based on an embodiment of the present disclosure.The embodiment of FIG. 13 may be combined with various embodiments ofthe present disclosure.

Referring to FIG. 13 , in step S1310, the base station may transmitinformation related to SL resource(s) and information related to a PUCCHresource to the TX UE. For example, the base station may transmit theinformation related to the SL resource(s) to the TX UE through a SL CG(e.g., DCI and/or RRC message). For example, the base station maytransmit the information related to the PUCCH resource to the TX UEthrough the DCI and/or the RRC message.

In step S1320, the TX UE may obtain/generate a HARQ disable MAC PDU. Forexample, if the TX UE transmits the HARQ disable MAC PDU to the RX UE,the TX UE may transmit the HARQ disable MAC PDU to the RX UE by using aninitial transmission resource and/or retransmission resource(s)scheduled/allocated by the SL CG. For example, the TX UE may performinitial transmission and blind retransmission for the HARQ disable MACPDU.

In step S1330, the TX UE may determine that additional retransmission isrequired. In this case, for example, the TX UE may not be able toperform necessary retransmission by using the initial transmissionresource and/or the retransmission resource(s) scheduled by the basestation through the SL CG. Alternatively, for example, the TX UE may notbe able to perform retransmission by the maximum number ofretransmissions by using the initial transmission resource and/or theretransmission resource(s) scheduled by the base station through the SLCG. Alternatively, for example, if the TX UE performs retransmission byusing resource(s) in the next period scheduled by the base stationthrough the SL CG, the TX UE may determine that the TX UE does notsuccessfully complete SL transmission within packet delay budget (PDB).Alternatively, for example, the TX UE may determine that there is no SLgrant available for retransmission.

In the above-described case, in step S1340, the TX UE may transmit HARQNACK to the base station by using the PUCCH resource related toresource(s) scheduled/allocated by the SL CG. Through this, the TX UEmay request resource(s) for retransmission of the HARQ disable MAC PDUfrom the base station. Through this operation, if the TX UE performingblind retransmission for the HARQ disable MAC PDU fails to perform allnecessary retransmissions, the TX UE may request the base station toallocate additional retransmission resource(s) by using the PUCCHresource.

FIG. 14 shows a procedure for a TX UE to request retransmissionresource(s) in case a base station allocates SL resource(s) and a PUCCHresource to the TX UE, based on an embodiment of the present disclosure.The embodiment of FIG. 14 may be combined with various embodiments ofthe present disclosure.

Referring to FIG. 14 , in step S1410, the base station may transmitinformation related to SL resource(s) and information related to a PUCCHresource to the TX UE. For example, the base station may transmit theinformation related to the SL resource(s) and the information related tothe PUCCH resource to the TX UE through a DG (e.g., DCI). For example,the base station may transmit the information related to the SLresource(s) and the information related to the PUCCH resource to the TXUE through a CG (e.g., RRC message and/or DCI).

In step S1420, the TX UE may obtain a MAC PDU. For example, the MAC PDUmay include logical channel(s) configured with HARQ feedback disabled,but it may not include logical channel(s) configured with HARQ feedbackenabled. For example, the MAC PDU may include packet(s) related tological channel(s) configured with HARQ feedback disabled, but it maynot include packet(s) related to logical channel(s) configured with HARQfeedback enabled.

In step S1430, the TX UE may transmit a PSCCH to the RX UE by using theSL resource(s). In step S1440, the TX UE may transmit a PSSCH related tothe PSCCH to the RX UE by using the SL resource(s). For example, the TXUE may transmit the obtained MAC PDU through the PSSCH.

In step S1450, the TX UE may determine that i) retransmission of the MACPDU is required, and ii) there is no SL resource/grant available forretransmission of the MAC PDU. For example, the TX UE may determine thatSL HARQ feedback has been disabled for the logical channel(s) in the MACPDU required to be retransmitted and no sidelink grant is available forretransmission of the MAC PDU. In this case, in step S1460, the TX UEmay transmit NACK information to the base station by using the PUCCHresource. Accordingly, the base station may allocate additionalretransmission resource(s) to the TX UE based on the NACK information.

Based on an embodiment of the present disclosure, in case the TX UEtransmits a HARQ disable MAC PDU to the RX UE, the TX UE may requestallocation of retransmission resource(s) from the base station inadvance by using a pre-configured PUCCH resource. Herein, for example,the pre-configured PUCCH resource may be a PUCCH resource which is notrelated to resource(s) scheduled by the base station through a SL grant.For example, the pre-configured PUCCH resource may be a PUCCH resourceallocated to the TX UE from the base station before the base stationschedules SL resource(s) to the TX UE through the SL grant. For example,the TX UE has been allocated the pre-configured PUCCH resource for otherpurposes (e.g., a purpose other than SL HARQ feedback report purpose)from the base station, but the TX UE may not yet use the pre-configuredPUCCH resource. Alternatively, for example, the TX UE was going to usethe pre-configured PUCCH resource for other purposes, but the TX UE mayuse the pre-configured PUCCH resource to secure retransmissionresource(s) in advance. For example, in order for the TX UE to performthe above-described operation, the TX UE may request retransmissionresource(s) from the base station by using any PUCCH resource(s) locatedafter a time when the SL grant is received from the base station. Thatis, the TX UE may request retransmission resource(s) from the basestation by using any PUCCH resource(s) available after the time when theSL grant is received from the base station. In this case, for example,the TX UE may determine/predict that the TX UE cannot perform allretransmissions or retransmissions as many as the maximum number ofretransmissions by using SL resource(s) allocated through the SL grantfrom the base station. Alternatively, for example, only if the maximumnumber of retransmissions configured to the MAC PDU to be transmitted bythe TX UE is equal to or greater than a specific number, the TX UE mayperform the above-described operation.

For example, in case the TX UE transmits a HARQ enable MAC PDU or a HARQdisable MAC PDU to the RX UE, the TX UE may report SL HARQ feedback tothe base station by using a PUCCH resource related to a SL grant (e.g.,a PUCCH resource indicated by the SL grant). In this case, the TX UE maytransmit SL HARQ feedback to the base station through a PUCCH inconsideration of packet delay budget (PDB) of the HARQ enable MAC PDU orthe HARQ disable MAC PDU. For example, if the TX UE which intends torequest additional retransmission resource(s) through a PUCCH determinesthat the TX UE cannot transmit SL information within PDB by using theadditional retransmission resource(s) allocated from the base station,the TX UE may not report SL HARQ feedback to the base station. Forexample, if the TX UE which intends to request additional retransmissionresource(s) through a PUCCH determines that the TX UE can transmit SLinformation within PDB by using the additional retransmissionresource(s) allocated from the base station, the TX UE may report SLHARQ feedback to the base station by using the PUCCH resource. Inaddition, the base station may allocate additional retransmissionresource(s) to the TX UE based on the SL HARQ feedback (e.g., HARQNACK).

2. CASE B

Based on an embodiment of the present disclosure, the base station mayschedule/allocate only SL resource(s) to the TX UE. On the other hand,the base station may not schedule/allocate a PUCCH resource related tothe SL resource(s) to the TX UE. In this case, the TX UE may transmit aHARQ enable MAC PDU and a HARQ disable MAC PDU to the RX UE by using theSL resource(s) allocated from the base station through a SL grant.

In this case, for example, if the TX UE transmits the HARQ enable MACPDU and/or the HARQ disable MAC PDU to the RX UE, the TX UE may not beable to request additional retransmission resource(s) from the basestation. For example, if the maximum number of retransmissions of the TXUE is 10, the TX UE may not be able to perform the remaining 7transmissions if the base station allocates up to 3 resources to the TXUE through a SL DG. Naturally, the TX UE and the base station knowmaximum number of retransmissions with each other, and the TX UE mayexpect to receive multiple SL DGs from the base station to satisfy allof the maximum number of retransmissions. However, due to the burden ofresource scheduling of the base station, the base station may not beable to transmit multiple SL DGs to the TX UE. In this case, the TX UEmay have to find a way to request additional resource(s). If there is noway for the TX UE to request additional resource(s), the TX UE may notbe able to perform additional retransmission. Accordingly, in the caseof CASE B, a method for the TX UE to request additional retransmissionresource(s) from the base station and an apparatus supporting the same,or an optimization method of the UE and an apparatus supporting the sameare proposed.

First, a restriction in which the TX UE can use a SL grant that does notindicate a PUCCH resource is proposed. For example, only if the maximumnumber of retransmissions of a MAC PDU to be transmitted by the TX UE orthe number of retransmissions configured by the TX UE is less than aspecific number or a specific threshold, the TX UE may perform SLtransmission by using SL resource(s) allocated through a SL grant thatdoes not indicate a PUCCH resource. In this case, since the base stationdoes not allocate a PUCCH resource related to the SL resource(s) to theTX UE, the TX UE may not be able to report SL HARQ feedback to the basestation.

For example, a SL DG (e.g., DCI) which is transmitted by the basestation to the TX UE in resource allocation mode 1 may schedule aresource related to one initial transmission and resources related totwo retransmissions to the TX UE at most. That is, the SL DG mayschedule resources related to a total of three transmissions to the TXUE. Accordingly, if the number of retransmissions of a MAC PDU to betransmitted by the TX UE is less than three, the TX UE may perform SLtransmission by using SL resource(s) allocated through the SL grant thatdoes not indicate the PUCCH resource. Naturally, the above-describedlimitation may be fixedly set to two retransmissions, but may be setdifferently depending on the channel condition or the congestion levelof the TX UE. Through the above-mentioned limitation, it is possible toprevent the problem that the TX UE cannot further request additionalretransmission resource(s) from the base station by using the PUCCHresource.

Alternatively, for example, it is assumed that the base stationtransmits a SL grant that does not indicate a PUCCH resource to the TXUE, and the TX UE transmits a MAC PDU to the RX UE by using SLresource(s) allocated through the SL grant. Furthermore, it is assumedthat the TX UE requires additional retransmission resource(s) eventhough the TX UE has used all the SL resource(s) allocated through theSL grant. For example, it is assumed that the TX UE may not reach themaximum number of retransmissions of the TX UE even though all SLresource(s) allocated through the SL grant have been used, andaccordingly, the TX UE requires additional retransmission resource(s).Accordingly, the TX UE may trigger a new scheduling request (SR) and/ora buffer status report (BSR) procedure. For example, the TX UE maytransmit a SR and/or a BSR to the base station.

In the above-described case, the TX UE may transmit a new SR to the basestation, whereas the TX UE may not transmit a BSR to the base station.For example, since the BSR may be replaced with a BSR performed in theprevious initial transmission, the TX UE may transmit a new SR to thebase station, whereas the TX UE may not transmit a BSR to the basestation. That is, the TX UE may not repeatedly transmit the BSR to thebase station in order to request additional retransmission resource(s)for the initial transmission. In addition, for example, the base stationmay allocate resource(s) to the TX UE based on the BSR previouslytransmitted by the TX UE.

Based on various embodiments of the present disclosure, if the UE cannotperform SL retransmission by using resource(s) allocated from the basestation, the UE may request retransmission resource(s) from the basestation to perform additional SL retransmission. In particular, if theUE is allocated a PUCCH resource from the base station, even though theUE has transmitted a HARQ disable MAC PDU, if the UE determines thatthere is no SL grant available for retransmission, the UE may transmitNACK information to the base station through the PUCCH. Accordingly,there may be an effect that the UE can be allocated additionalretransmission resource(s) from the base station.

FIG. 15 shows a method for a first device to perform wirelesscommunication, based on an embodiment of the present disclosure. Theembodiment of FIG. 15 may be combined with various embodiments of thepresent disclosure.

Referring to FIG. 15 , in step S1510, the first device may receive, froma base station, information related to a first sidelink (SL) resourceand information related to a first physical uplink control channel(PUCCH) resource. In step S1520, the first device may transmit, to asecond device, a medium access control (MAC) packet data unit (PDU) byusing the first SL resource. For example, the MAC PDU may include apacket related to a logical channel for which hybrid automatic repeatrequest (HARQ) feedback is disabled, and the MAC PDU may include nopacket related to a logical channel for which HARQ feedback is enabled.In step S1530, the first device may determine that retransmission of theMAC PDU is required. In step S1540, the first device may transmit, tothe base station, NACK information by using the first PUCCH resourcebased on no SL grant available for retransmission of the MAC PDU.

For example, the first PUCCH resource may be a resource related to thefirst SL resource. For example, the NACK information may be transmittedto request the base station for a resource for retransmission of the MACPDU. Additionally, for example, the first device may receive, from thebase station, information related to a second SL resource, in responseto the NACK information. Additionally, for example, the first device mayretransmit, to the second device, the MAC PDU by using the second SLresource.

For example, the logical channel for which HARQ feedback is disabled andthe logical channel for which HARQ feedback is enabled may not bemultiplexed simultaneously into the MAC PDU.

Additionally, for example, the first device may transmit, to the basestation, information related to a request for a retransmission resourceby using a second PUCCH resource, based on transmitting the MAC PDU tothe second device. For example, the second PUCCH resource may be aresource not related to the first SL resource. For example, theinformation related to the request for the retransmission resource maybe transmitted to the base station, before the first device determinesthat the retransmission of the MAC PDU is required.

For example, the first SL resource may include a PSCCH resource and aPSSCH resource. For example, the first SL resource may include at leastone of a resource for initial transmission and a resource forretransmission. For example, the information related to the first SLresource may be received through a SL grant. For example, the SL grantmay be a dynamic grant or a configured grant.

The proposed method can be applied to the device(s) described below.First, the processor 102 of the first device 100 may control thetransceiver 106 to receive, from a base station, information related toa first sidelink (SL) resource and information related to a firstphysical uplink control channel (PUCCH) resource. In addition, theprocessor 102 of the first device 100 may control the transceiver 106 totransmit, to a second device, a medium access control (MAC) packet dataunit (PDU) by using the first SL resource. For example, the MAC PDU mayinclude a packet related to a logical channel for which hybrid automaticrepeat request (HARQ) feedback is disabled, and the MAC PDU may includeno packet related to a logical channel for which HARQ feedback isenabled. In addition, the processor 102 of the first device 100 maydetermine that retransmission of the MAC PDU is required. In addition,the processor 102 of the first device 100 may control the transceiver106 to transmit, to the base station, NACK information by using thefirst PUCCH resource based on no SL grant available for retransmissionof the MAC PDU.

Based on an embodiment of the present disclosure, a first deviceconfigured to perform wireless communication may be provided. Forexample, the first device may comprise: one or more memories storinginstructions; one or more transceivers; and one or more processorsconnected to the one or more memories and the one or more transceivers.For example, the one or more processors may execute the instructions to:receive, from a base station, information related to a first sidelink(SL) resource and information related to a first physical uplink controlchannel (PUCCH) resource; transmit, to a second device, a medium accesscontrol (MAC) packet data unit (PDU) by using the first SL resource,wherein the MAC PDU includes a packet related to a logical channel forwhich hybrid automatic repeat request (HARQ) feedback is disabled, andwherein the MAC PDU includes no packet related to a logical channel forwhich HARQ feedback is enabled; determine that retransmission of the MACPDU is required; and transmit, to the base station, NACK information byusing the first PUCCH resource based on no SL grant available forretransmission of the MAC PDU.

Based on an embodiment of the present disclosure, an apparatusconfigured to control a first user equipment (UE) performing wirelesscommunication may be provided. For example, the apparatus may comprise:one or more processors; and one or more memories operably connected tothe one or more processors and storing instructions. For example, theone or more processors may execute the instructions to: receive, from abase station, information related to a first sidelink (SL) resource andinformation related to a first physical uplink control channel (PUCCH)resource; transmit, to a second UE, a medium access control (MAC) packetdata unit (PDU) by using the first SL resource, wherein the MAC PDUincludes a packet related to a logical channel for which hybridautomatic repeat request (HARQ) feedback is disabled, and wherein theMAC PDU includes no packet related to a logical channel for which HARQfeedback is enabled; determine that retransmission of the MAC PDU isrequired; and transmit, to the base station, NACK information by usingthe first PUCCH resource based on no SL grant available forretransmission of the MAC PDU.

Based on an embodiment of the present disclosure, a non-transitorycomputer-readable storage medium storing instructions may be provided.For example, the instructions, when executed, may cause a first deviceto: receive, from a base station, information related to a firstsidelink (SL) resource and information related to a first physicaluplink control channel (PUCCH) resource; transmit, to a second device, amedium access control (MAC) packet data unit (PDU) by using the first SLresource, wherein the MAC PDU includes a packet related to a logicalchannel for which hybrid automatic repeat request (HARQ) feedback isdisabled, and wherein the MAC PDU includes no packet related to alogical channel for which HARQ feedback is enabled; determine thatretransmission of the MAC PDU is required; and transmit, to the basestation, NACK information by using the first PUCCH resource based on noSL grant available for retransmission of the MAC PDU.

Various embodiments of the present disclosure may be combined with eachother.

Hereinafter, device(s) to which various embodiments of the presentdisclosure can be applied will be described.

The various descriptions, functions, procedures, proposals, methods,and/or operational flowcharts of the present disclosure described inthis document may be applied to, without being limited to, a variety offields requiring wireless communication/connection (e.g., 5G) betweendevices.

Hereinafter, a description will be given in more detail with referenceto the drawings. In the following drawings/description, the samereference symbols may denote the same or corresponding hardware blocks,software blocks, or functional blocks unless described otherwise.

FIG. 16 shows a communication system 1, based on an embodiment of thepresent disclosure.

Referring to FIG. 16 , a communication system 1 to which variousembodiments of the present disclosure are applied includes wirelessdevices, Base Stations (BSs), and a network. Herein, the wirelessdevices represent devices performing communication using Radio AccessTechnology (RAT) (e.g., 5G New RAT (NR)) or Long-Term Evolution (LTE))and may be referred to as communication/radio/5G devices. The wirelessdevices may include, without being limited to, a robot 100 a, vehicles100 b-1 and 100 b-2, an eXtended Reality (XR) device 100 c, a hand-helddevice 100 d, a home appliance 100 e, an Internet of Things (IoT) device100 f, and an Artificial Intelligence (AI) device/server 400. Forexample, the vehicles may include a vehicle having a wirelesscommunication function, an autonomous vehicle, and a vehicle capable ofperforming communication between vehicles. Herein, the vehicles mayinclude an Unmanned Aerial Vehicle (UAV) (e.g., a drone). The XR devicemay include an Augmented Reality (AR)/Virtual Reality (VR)/Mixed Reality(MR) device and may be implemented in the form of a Head-Mounted Device(HMD), a Head-Up Display (HUD) mounted in a vehicle, a television, asmartphone, a computer, a wearable device, a home appliance device, adigital signage, a vehicle, a robot, etc. The hand-held device mayinclude a smartphone, a smartpad, a wearable device (e.g., a smartwatchor a smartglasses), and a computer (e.g., a notebook). The homeappliance may include a TV, a refrigerator, and a washing machine. TheIoT device may include a sensor and a smartmeter. For example, the BSsand the network may be implemented as wireless devices and a specificwireless device 200 a may operate as a BS/network node with respect toother wireless devices.

The wireless devices 100 a to 100 f may be connected to the network 300via the BSs 200. An AI technology may be applied to the wireless devices100 a to 100 f and the wireless devices 100 a to 100 f may be connectedto the AI server 400 via the network 300. The network 300 may beconfigured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g.,NR) network. Although the wireless devices 100 a to 100 f maycommunicate with each other through the BSs 200/network 300, thewireless devices 100 a to 100 f may perform direct communication (e.g.,sidelink communication) with each other without passing through theBSs/network. For example, the vehicles 100 b-1 and 100 b-2 may performdirect communication (e.g. Vehicle-to-Vehicle(V2V)/Vehicle-to-everything (V2X) communication). The IoT device (e.g.,a sensor) may perform direct communication with other IoT devices (e.g.,sensors) or other wireless devices 100 a to 100 f.

Wireless communication/connections 150 a, 150 b, or 150 c may beestablished between the wireless devices 100 a to 100 f/BS 200, or BS200/BS 200. Herein, the wireless communication/connections may beestablished through various RATs (e.g., 5G NR) such as uplink/downlinkcommunication 150 a, sidelink communication 150 b (or, D2Dcommunication), or inter BS communication (e.g., relay, IntegratedAccess Backhaul (IAB)). The wireless devices and the BSs/the wirelessdevices may transmit/receive radio signals to/from each other throughthe wireless communication/connections 150 a and 150 b. For example, thewireless communication/connections 150 a and 150 b may transmit/receivesignals through various physical channels. To this end, at least a partof various configuration information configuring processes, varioussignal processing processes (e.g., channel encoding/decoding,modulation/demodulation, and resource mapping/demapping), and resourceallocating processes, for transmitting/receiving radio signals, may beperformed based on the various proposals of the present disclosure.

FIG. 17 shows wireless devices, based on an embodiment of the presentdisclosure.

Referring to FIG. 17 , a first wireless device 100 and a second wirelessdevice 200 may transmit radio signals through a variety of RATs (e.g.,LTE and NR). Herein, {the first wireless device 100 and the secondwireless device 200} may correspond to {the wireless device 100 x andthe BS 200} and/or {the wireless device 100 x and the wireless device100 x} of FIG. 16 .

The first wireless device 100 may include one or more processors 102 andone or more memories 104 and additionally further include one or moretransceivers 106 and/or one or more antennas 108. The processor(s) 102may control the memory(s) 104 and/or the transceiver(s) 106 and may beconfigured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 102 may process informationwithin the memory(s) 104 to generate first information/signals and thentransmit radio signals including the first information/signals throughthe transceiver(s) 106. The processor(s) 102 may receive radio signalsincluding second information/signals through the transceiver 106 andthen store information obtained by processing the secondinformation/signals in the memory(s) 104. The memory(s) 104 may beconnected to the processor(s) 102 and may store a variety of informationrelated to operations of the processor(s) 102. For example, thememory(s) 104 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 102or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 102 and the memory(s) 104 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 106 may be connected to the processor(s) 102 andtransmit and/or receive radio signals through one or more antennas 108.Each of the transceiver(s) 106 may include a transmitter and/or areceiver. The transceiver(s) 106 may be interchangeably used with RadioFrequency (RF) unit(s). In the present disclosure, the wireless devicemay represent a communication modem/circuit/chip.

The second wireless device 200 may include one or more processors 202and one or more memories 204 and additionally further include one ormore transceivers 206 and/or one or more antennas 208. The processor(s)202 may control the memory(s) 204 and/or the transceiver(s) 206 and maybe configured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 202 may process informationwithin the memory(s) 204 to generate third information/signals and thentransmit radio signals including the third information/signals throughthe transceiver(s) 206. The processor(s) 202 may receive radio signalsincluding fourth information/signals through the transceiver(s) 106 andthen store information obtained by processing the fourthinformation/signals in the memory(s) 204. The memory(s) 204 may beconnected to the processor(s) 202 and may store a variety of informationrelated to operations of the processor(s) 202. For example, thememory(s) 204 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 202or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 202 and the memory(s) 204 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 206 may be connected to the processor(s) 202 andtransmit and/or receive radio signals through one or more antennas 208.Each of the transceiver(s) 206 may include a transmitter and/or areceiver. The transceiver(s) 206 may be interchangeably used with RFunit(s). In the present disclosure, the wireless device may represent acommunication modem/circuit/chip.

Hereinafter, hardware elements of the wireless devices 100 and 200 willbe described more specifically. One or more protocol layers may beimplemented by, without being limited to, one or more processors 102 and202. For example, the one or more processors 102 and 202 may implementone or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP,RRC, and SDAP). The one or more processors 102 and 202 may generate oneor more Protocol Data Units (PDUs) and/or one or more Service Data Unit(SDUs) according to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document. Theone or more processors 102 and 202 may generate messages, controlinformation, data, or information according to the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document. The one or more processors 102 and 202 maygenerate signals (e.g., baseband signals) including PDUs, SDUs,messages, control information, data, or information according to thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document and provide thegenerated signals to the one or more transceivers 106 and 206. The oneor more processors 102 and 202 may receive the signals (e.g., basebandsignals) from the one or more transceivers 106 and 206 and acquire thePDUs, SDUs, messages, control information, data, or informationaccording to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.

The one or more processors 102 and 202 may be referred to ascontrollers, microcontrollers, microprocessors, or microcomputers. Theone or more processors 102 and 202 may be implemented by hardware,firmware, software, or a combination thereof. As an example, one or moreApplication Specific Integrated Circuits (ASICs), one or more DigitalSignal Processors (DSPs), one or more Digital Signal Processing Devices(DSPDs), one or more Programmable Logic Devices (PLDs), or one or moreField Programmable Gate Arrays (FPGAs) may be included in the one ormore processors 102 and 202. The descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument may be implemented using firmware or software and the firmwareor software may be configured to include the modules, procedures, orfunctions. Firmware or software configured to perform the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be included in the one or more processors102 and 202 or stored in the one or more memories 104 and 204 so as tobe driven by the one or more processors 102 and 202. The descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be implemented using firmware or softwarein the form of code, commands, and/or a set of commands

The one or more memories 104 and 204 may be connected to the one or moreprocessors 102 and 202 and store various types of data, signals,messages, information, programs, code, instructions, and/or commands Theone or more memories 104 and 204 may be configured by Read-Only Memories(ROMs), Random Access Memories (RAMs), Electrically ErasableProgrammable Read-Only Memories (EPROMs), flash memories, hard drives,registers, cash memories, computer-readable storage media, and/orcombinations thereof. The one or more memories 104 and 204 may belocated at the interior and/or exterior of the one or more processors102 and 202. The one or more memories 104 and 204 may be connected tothe one or more processors 102 and 202 through various technologies suchas wired or wireless connection.

The one or more transceivers 106 and 206 may transmit user data, controlinformation, and/or radio signals/channels, mentioned in the methodsand/or operational flowcharts of this document, to one or more otherdevices. The one or more transceivers 106 and 206 may receive user data,control information, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, from one or moreother devices. For example, the one or more transceivers 106 and 206 maybe connected to the one or more processors 102 and 202 and transmit andreceive radio signals. For example, the one or more processors 102 and202 may perform control so that the one or more transceivers 106 and 206may transmit user data, control information, or radio signals to one ormore other devices. The one or more processors 102 and 202 may performcontrol so that the one or more transceivers 106 and 206 may receiveuser data, control information, or radio signals from one or more otherdevices. The one or more transceivers 106 and 206 may be connected tothe one or more antennas 108 and 208 and the one or more transceivers106 and 206 may be configured to transmit and receive user data, controlinformation, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, through the one ormore antennas 108 and 208. In this document, the one or more antennasmay be a plurality of physical antennas or a plurality of logicalantennas (e.g., antenna ports). The one or more transceivers 106 and 206may convert received radio signals/channels etc. from RF band signalsinto baseband signals in order to process received user data, controlinformation, radio signals/channels, etc. using the one or moreprocessors 102 and 202. The one or more transceivers 106 and 206 mayconvert the user data, control information, radio signals/channels, etc.processed using the one or more processors 102 and 202 from the baseband signals into the RF band signals. To this end, the one or moretransceivers 106 and 206 may include (analog) oscillators and/orfilters.

FIG. 18 shows a signal process circuit for a transmission signal, basedon an embodiment of the present disclosure.

Referring to FIG. 18 , a signal processing circuit 1000 may includescramblers 1010, modulators 1020, a layer mapper 1030, a precoder 1040,resource mappers 1050, and signal generators 1060. An operation/functionof FIG. 18 may be performed, without being limited to, the processors102 and 202 and/or the transceivers 106 and 206 of FIG. 17 . Hardwareelements of FIG. 18 may be implemented by the processors 102 and 202and/or the transceivers 106 and 206 of FIG. 17 . For example, blocks1010 to 1060 may be implemented by the processors 102 and 202 of FIG. 17. Alternatively, the blocks 1010 to 1050 may be implemented by theprocessors 102 and 202 of FIG. 17 and the block 1060 may be implementedby the transceivers 106 and 206 of FIG. 17 .

Codewords may be converted into radio signals via the signal processingcircuit 1000 of FIG. 18 . Herein, the codewords are encoded bitsequences of information blocks. The information blocks may includetransport blocks (e.g., a UL-SCH transport block, a DL-SCH transportblock). The radio signals may be transmitted through various physicalchannels (e.g., a PUSCH and a PDSCH).

Specifically, the codewords may be converted into scrambled bitsequences by the scramblers 1010. Scramble sequences used for scramblingmay be generated based on an initialization value, and theinitialization value may include ID information of a wireless device.The scrambled bit sequences may be modulated to modulation symbolsequences by the modulators 1020. A modulation scheme may includepi/2-Binary Phase Shift Keying (pi/2-BPSK), m-Phase Shift Keying(m-PSK), and m-Quadrature Amplitude Modulation (m-QAM). Complexmodulation symbol sequences may be mapped to one or more transportlayers by the layer mapper 1030. Modulation symbols of each transportlayer may be mapped (precoded) to corresponding antenna port(s) by theprecoder 1040. Outputs z of the precoder 1040 may be obtained bymultiplying outputs y of the layer mapper 1030 by an N*M precodingmatrix W. Herein, N is the number of antenna ports and M is the numberof transport layers. The precoder 1040 may perform precoding afterperforming transform precoding (e.g., DFT) for complex modulationsymbols. Alternatively, the precoder 1040 may perform precoding withoutperforming transform precoding.

The resource mappers 1050 may map modulation symbols of each antennaport to time-frequency resources. The time-frequency resources mayinclude a plurality of symbols (e.g., a CP-OFDMA symbols and DFT-s-OFDMAsymbols) in the time domain and a plurality of subcarriers in thefrequency domain. The signal generators 1060 may generate radio signalsfrom the mapped modulation symbols and the generated radio signals maybe transmitted to other devices through each antenna. For this purpose,the signal generators 1060 may include Inverse Fast Fourier Transform(IFFT) modules, Cyclic Prefix (CP) inserters, Digital-to-AnalogConverters (DACs), and frequency up-converters.

Signal processing procedures for a signal received in the wirelessdevice may be configured in a reverse manner of the signal processingprocedures 1010 to 1060 of FIG. 18 . For example, the wireless devices(e.g., 100 and 200 of FIG. 17 ) may receive radio signals from theexterior through the antenna ports/transceivers. The received radiosignals may be converted into baseband signals through signal restorers.To this end, the signal restorers may include frequency downlinkconverters, Analog-to-Digital Converters (ADCs), CP remover, and FastFourier Transform (FFT) modules. Next, the baseband signals may berestored to codewords through a resource demapping procedure, apostcoding procedure, a demodulation processor, and a descramblingprocedure. The codewords may be restored to original information blocksthrough decoding. Therefore, a signal processing circuit (notillustrated) for a reception signal may include signal restorers,resource demappers, a postcoder, demodulators, descramblers, anddecoders.

FIG. 19 shows another example of a wireless device, based on anembodiment of the present disclosure. The wireless device may beimplemented in various forms according to a use-case/service (refer toFIG. 16 ).

Referring to FIG. 19 , wireless devices 100 and 200 may correspond tothe wireless devices 100 and 200 of FIG. 17 and may be configured byvarious elements, components, units/portions, and/or modules. Forexample, each of the wireless devices 100 and 200 may include acommunication unit 110, a control unit 120, a memory unit 130, andadditional components 140. The communication unit may include acommunication circuit 112 and transceiver(s) 114. For example, thecommunication circuit 112 may include the one or more processors 102 and202 and/or the one or more memories 104 and 204 of FIG. 17 . Forexample, the transceiver(s) 114 may include the one or more transceivers106 and 206 and/or the one or more antennas 108 and 208 of FIG. 17 . Thecontrol unit 120 is electrically connected to the communication unit110, the memory 130, and the additional components 140 and controlsoverall operation of the wireless devices. For example, the control unit120 may control an electric/mechanical operation of the wireless devicebased on programs/code/commands/information stored in the memory unit130. The control unit 120 may transmit the information stored in thememory unit 130 to the exterior (e.g., other communication devices) viathe communication unit 110 through a wireless/wired interface or store,in the memory unit 130, information received through the wireless/wiredinterface from the exterior (e.g., other communication devices) via thecommunication unit 110.

The additional components 140 may be variously configured according totypes of wireless devices. For example, the additional components 140may include at least one of a power unit/battery, input/output (I/O)unit, a driving unit, and a computing unit. The wireless device may beimplemented in the form of, without being limited to, the robot (100 aof FIG. 16 ), the vehicles (100 b-1 and 100 b-2 of FIG. 16 ), the XRdevice (100 c of FIG. 16 ), the hand-held device (100 d of FIG. 16 ),the home appliance (100 e of FIG. 16 ), the IoT device (100 f of FIG. 16), a digital broadcast terminal, a hologram device, a public safetydevice, an MTC device, a medicine device, a fintech device (or a financedevice), a security device, a climate/environment device, the AIserver/device (400 of FIG. 16 ), the BSs (200 of FIG. 16 ), a networknode, etc. The wireless device may be used in a mobile or fixed placeaccording to a use-example/service.

In FIG. 19 , the entirety of the various elements, components,units/portions, and/or modules in the wireless devices 100 and 200 maybe connected to each other through a wired interface or at least a partthereof may be wireles sly connected through the communication unit 110.For example, in each of the wireless devices 100 and 200, the controlunit 120 and the communication unit 110 may be connected by wire and thecontrol unit 120 and first units (e.g., 130 and 140) may be wirelesslyconnected through the communication unit 110. Each element, component,unit/portion, and/or module within the wireless devices 100 and 200 mayfurther include one or more elements. For example, the control unit 120may be configured by a set of one or more processors. As an example, thecontrol unit 120 may be configured by a set of a communication controlprocessor, an application processor, an Electronic Control Unit (ECU), agraphical processing unit, and a memory control processor. As anotherexample, the memory 130 may be configured by a Random Access Memory(RAM), a Dynamic RAM (DRAM), a Read Only Memory (ROM)), a flash memory,a volatile memory, a non-volatile memory, and/or a combination thereof.

Hereinafter, an example of implementing FIG. 19 will be described indetail with reference to the drawings.

FIG. 20 shows a hand-held device, based on an embodiment of the presentdisclosure. The hand-held device may include a smartphone, a smartpad, awearable device (e.g., a smartwatch or a smartglasses), or a portablecomputer (e.g., a notebook). The hand-held device may be referred to asa mobile station (MS), a user terminal (UT), a Mobile Subscriber Station(MSS), a Subscriber Station (SS), an Advanced Mobile Station (AMS), or aWireless Terminal (WT).

Referring to FIG. 20 , a hand-held device 100 may include an antennaunit 108, a communication unit 110, a control unit 120, a memory unit130, a power supply unit 140 a, an interface unit 140 b, and an I/O unit140 c. The antenna unit 108 may be configured as a part of thecommunication unit 110. Blocks 110 to 130/140 a to 140 c correspond tothe blocks 110 to 130/140 of FIG. 19 , respectively.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from other wireless devices or BSs. Thecontrol unit 120 may perform various operations by controllingconstituent elements of the hand-held device 100. The control unit 120may include an Application Processor (AP). The memory unit 130 may storedata/parameters/programs/code/commands needed to drive the hand-helddevice 100. The memory unit 130 may store input/output data/information.The power supply unit 140 a may supply power to the hand-held device 100and include a wired/wireless charging circuit, a battery, etc. Theinterface unit 140 b may support connection of the hand-held device 100to other external devices. The interface unit 140 b may include variousports (e.g., an audio I/O port and a video I/O port) for connection withexternal devices. The I/O unit 140 c may input or output videoinformation/signals, audio information/signals, data, and/or informationinput by a user. The I/O unit 140 c may include a camera, a microphone,a user input unit, a display unit 140 d, a speaker, and/or a hapticmodule.

As an example, in the case of data communication, the I/O unit 140 c mayacquire information/signals (e.g., touch, text, voice, images, or video)input by a user and the acquired information/signals may be stored inthe memory unit 130. The communication unit 110 may convert theinformation/signals stored in the memory into radio signals and transmitthe converted radio signals to other wireless devices directly or to aBS. The communication unit 110 may receive radio signals from otherwireless devices or the BS and then restore the received radio signalsinto original information/signals. The restored information/signals maybe stored in the memory unit 130 and may be output as various types(e.g., text, voice, images, video, or haptic) through the I/O unit 140c.

FIG. 21 shows a vehicle or an autonomous vehicle, based on an embodimentof the present disclosure. The vehicle or autonomous vehicle may beimplemented by a mobile robot, a car, a train, a manned/unmanned AerialVehicle (AV), a ship, etc.

Referring to FIG. 21 , a vehicle or autonomous vehicle 100 may includean antenna unit 108, a communication unit 110, a control unit 120, adriving unit 140 a, a power supply unit 140 b, a sensor unit 140 c, andan autonomous driving unit 140 d. The antenna unit 108 may be configuredas a part of the communication unit 110. The blocks 110/130/140 a to 140d correspond to the blocks 110/130/140 of FIG. 19 , respectively.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from external devices such as othervehicles, BSs (e.g., gNBs and road side units), and servers. The controlunit 120 may perform various operations by controlling elements of thevehicle or the autonomous vehicle 100. The control unit 120 may includean Electronic Control Unit (ECU). The driving unit 140 a may cause thevehicle or the autonomous vehicle 100 to drive on a road. The drivingunit 140 a may include an engine, a motor, a powertrain, a wheel, abrake, a steering device, etc. The power supply unit 140 b may supplypower to the vehicle or the autonomous vehicle 100 and include awired/wireless charging circuit, a battery, etc. The sensor unit 140 cmay acquire a vehicle state, ambient environment information, userinformation, etc. The sensor unit 140 c may include an InertialMeasurement Unit (IMU) sensor, a collision sensor, a wheel sensor, aspeed sensor, a slope sensor, a weight sensor, a heading sensor, aposition module, a vehicle forward/backward sensor, a battery sensor, afuel sensor, a tire sensor, a steering sensor, a temperature sensor, ahumidity sensor, an ultrasonic sensor, an illumination sensor, a pedalposition sensor, etc. The autonomous driving unit 140 d may implementtechnology for maintaining a lane on which a vehicle is driving,technology for automatically adjusting speed, such as adaptive cruisecontrol, technology for autonomously driving along a determined path,technology for driving by automatically setting a path if a destinationis set, and the like.

For example, the communication unit 110 may receive map data, trafficinformation data, etc. from an external server. The autonomous drivingunit 140 d may generate an autonomous driving path and a driving planfrom the obtained data. The control unit 120 may control the drivingunit 140 a such that the vehicle or the autonomous vehicle 100 may movealong the autonomous driving path according to the driving plan (e.g.,speed/direction control). In the middle of autonomous driving, thecommunication unit 110 may aperiodically/periodically acquire recenttraffic information data from the external server and acquiresurrounding traffic information data from neighboring vehicles. In themiddle of autonomous driving, the sensor unit 140 c may obtain a vehiclestate and/or surrounding environment information. The autonomous drivingunit 140 d may update the autonomous driving path and the driving planbased on the newly obtained data/information. The communication unit 110may transfer information about a vehicle position, the autonomousdriving path, and/or the driving plan to the external server. Theexternal server may predict traffic information data using AItechnology, etc., based on the information collected from vehicles orautonomous vehicles and provide the predicted traffic information datato the vehicles or the autonomous vehicles.

Claims in the present description can be combined in a various way. Forinstance, technical features in method claims of the present descriptioncan be combined to be implemented or performed in an apparatus, andtechnical features in apparatus claims can be combined to be implementedor performed in a method. Further, technical features in method claim(s)and apparatus claim(s) can be combined to be implemented or performed inan apparatus. Further, technical features in method claim(s) andapparatus claim(s) can be combined to be implemented or performed in amethod.

1.-16. (canceled)
 17. A method for performing, by a first device,wireless communication, the method comprising: receiving, from a basestation, a first sidelink grant; obtaining a medium access control (MAC)packet data unit (PDU) for the first sidelink grant, wherein a logicalchannel configured with hybrid automatic repeat request (HARQ) feedbackdisabled and a logical channel configured with HARQ feedback enabledcannot be multiplexed into the MAC PDU; and transmitting, to the basestation, negative acknowledgement on a physical uplink control channel(PUCCH) resource, based on (i) the PUCCH resource configured for thefirst device, (ii) HARQ feedback disabled for the MAC PDU, and (iii) nosidelink grant available for next retransmission of the MAC PDU.
 18. Themethod of claim 17, wherein the MAC PDU includes data related to thelogical channel configured with the HARQ feedback disabled.
 19. Themethod of claim 18, wherein the MAC PDU includes no data related to thelogical channel configured with the HARQ feedback enabled.
 20. Themethod of claim 17, wherein, based on (i) the PUCCH resource configuredfor the first device, (ii) the HARQ feedback disabled for the MAC PDU,(iii) a maximum transmission number configured for the first sidelinkgrant, and (iv) a number of transmissions of the MAC PDU which is notreached the maximum transmission number, the negative acknowledgement istransmitted on the PUCCH resource to the base station.
 21. The method ofclaim 17, wherein the first sidelink grant is a sidelink dynamic grantor a sidelink configured grant.
 22. The method of claim 17, wherein thefirst sidelink grant is related to the PUCCH resource.
 23. The method ofclaim 17, further comprising: transmitting, to a second device, the MACPDU based on the first sidelink grant.
 24. The method of claim 17,wherein the negative acknowledgement is transmitted to request the basestation for a second sidelink grant for retransmission of the MAC PDU.25. The method of claim 24, further comprising: receiving, from the basestation, the second sidelink grant, in response to the negativeacknowledgement.
 26. The method of claim 25, further comprising:retransmitting, to the second device, the MAC PDU based on the secondsidelink grant.
 27. A first device adapted to perform wirelesscommunication, the first device comprising: one or more memories storinginstructions; one or more transceivers; and one or more processorsconnected to the one or more memories and the one or more transceivers,wherein the one or more processors execute the instructions to: controlthe one or more transceivers to receive, from a base station, a firstsidelink grant; obtain a medium access control (MAC) packet data unit(PDU) for the first sidelink grant, wherein a logical channel configuredwith hybrid automatic repeat request (HARQ) feedback disabled and alogical channel configured with HARQ feedback enabled cannot bemultiplexed into the MAC PDU; and control the one or more transceiversto transmit, to the base station, negative acknowledgement on a physicaluplink control channel (PUCCH) resource, based on (i) the PUCCH resourceconfigured for the first device, (ii) HARQ feedback disabled for the MACPDU, and (iii) no sidelink grant available for next retransmission ofthe MAC PDU.
 28. The first device of claim 27, wherein the MAC PDUincludes data related to the logical channel configured with the HARQfeedback disabled.
 29. The first device of claim 28, wherein the MAC PDUincludes no data related to the logical channel configured with the HARQfeedback enabled.
 30. The first device of claim 27, wherein, based on(i) the PUCCH resource configured for the first device, (ii) the HARQfeedback disabled for the MAC PDU, (iii) a maximum transmission numberconfigured for the first sidelink grant, and (iv) a number oftransmissions of the MAC PDU which is not reached the maximumtransmission number, the negative acknowledgement is transmitted on thePUCCH resource to the base station.
 31. The first device of claim 27,wherein the first sidelink grant is related to the PUCCH resource.
 32. Aprocessing device adapted to control a first device, the processingdevice comprising: one or more processors; and one or more memoriesoperably connected to the one or more processors and storinginstructions, wherein the one or more processors execute theinstructions to: receive, from a base station, a first sidelink grant;obtain a medium access control (MAC) packet data unit (PDU) for thefirst sidelink grant, wherein a logical channel configured with hybridautomatic repeat request (HARQ) feedback disabled and a logical channelconfigured with HARQ feedback enabled cannot be multiplexed into the MACPDU; and transmit, to the base station, negative acknowledgement on aphysical uplink control channel (PUCCH) resource, based on (i) the PUCCHresource configured for the first device, (ii) HARQ feedback disabledfor the MAC PDU, and (iii) no sidelink grant available for nextretransmission of the MAC PDU.
 33. The processing device of claim 32,wherein the MAC PDU includes data related to the logical channelconfigured with the HARQ feedback disabled.
 34. The processing device ofclaim 33, wherein the MAC PDU includes no data related to the logicalchannel configured with the HARQ feedback enabled.
 35. The processingdevice of claim 32, wherein, based on (i) the PUCCH resource configuredfor the first device, (ii) the HARQ feedback disabled for the MAC PDU,(iii) a maximum transmission number configured for the first sidelinkgrant, and (iv) a number of transmissions of the MAC PDU which is notreached the maximum transmission number, the negative acknowledgement istransmitted on the PUCCH resource to the base station.
 36. Theprocessing device of claim 32, wherein the first sidelink grant isrelated to the PUCCH resource.